188: Chapter 188 The Faint Light Illuminating the Maintenance Corridor

October 17th, 3:21 PM.

Qingling County, west side of Qingya Tunnel.

When two heavy box trucks drove into the warning zone, the rain in the sky turned into a dense, fine drizzle.

The low clouds in the valley pressed down extremely low, as if one could touch the gray mist with a mere stretch of the hand.

On both sides of the road were muddy waters washed down from the high slopes everywhere, and the engineering anti-slip mats temporarily laid on the ground had long been crushed by various heavy rescue vehicles beyond their original colors.

Further ahead, the asphalt road was abruptly cut off by several glaring yellow warning lines.

Inside the warning lines was another high-pressure world.

Red and blue police lights flashed alternately; fire trucks, ambulances, emergency communication vehicles with huge antennas deployed, and several engineering equipment with tracks stained with yellow mud were crowded into the narrow open space.

People wearing uniforms of different colors ran back and forth in the rain curtain, shouting loudly.

Several sets of high-power searchlights overhead had been lit in advance, illuminating the tragic entrance on the west side of Qingya Tunnel into a ghastly white.

Deep inside the tunnel, however, there was no light.

There was only a mass of darkness that seemed to devour everything.

Chen Yan pushed open the front passenger door and jumped out of the car. The soles of his shoes had just stepped onto the ground when they sank directly into a layer of cold, wet mud that covered the back of his feet.

He did not look down at his shoes, nor did he care about the mud splattered on his trouser legs.

The hydraulic rear door of the transport truck had already made a dull sound and slowly opened.

The two assembly engineers brought by Xu Man rushed into the truck compartment without hesitation, starting to quickly release the fixtures of the machines.

As for the two engineers sent by the client who had rich experience in underground utility tunnels, they turned around directly and strode towards the joint command post ahead.

A soaking wet emergency personnel ran over quickly and asked just one sentence at an extremely fast pace: "How soon can the equipment get off the truck?"

"Twelve minutes," Chen Yan replied.

"The command post requires that the description of the first action route must be completed within fifteen minutes."

"Alright."

Chen Yan raised his head and glanced above the tunnel.

The mountain was still running with water.

Turbid muddy water continuously poured down along the fractured concrete surface of the tunnel entrance, and several geological monitoring instruments were densely placed on the ground.

Several slender metal stakes were deeply driven into the slope and near the entrance, and the indicator lights at the top continuously flashed warning red lights in the rain.

Every few minutes, the high-pitch loudspeakers on site would repeat the evacuation boundary with a lifeless electronic voice.

[All non-essential personnel are strictly prohibited from entering the fifty-meter area in front of the tunnel entrance]

[The eastern landslide body still carries the risk of continuous downward movement]

[Pay attention to the rising water accumulation inside the tunnel, all groups keep communications clear]

Chen Yan put on a safety helmet, held the mission terminal in his arms, and lowered his head to drill into the temporary command area.

The so-called command area was actually just a few rain-proof tents spliced together, plus an emergency communication vehicle with its side expansion cabin deployed.

Several large screens on the walls of the vehicle compartment respectively displayed the design blueprints of Qingya Tunnel, real-time geological monitoring curves, and high-definition footage shot by drones at the periphery of the entrance.

The brief information of the seven missing personnel was listed separately on a whiteboard, with heavy exclamation marks drawn in red next to it.

Four daily tunnel maintenance personnel.

One truck driver.

Two road inspectors who lost contact after entering the tunnel from the east side.

"At 4:31 AM, the maintenance team used the fixed emergency telephone inside the tunnel to report outward that a large amount of muddy water was overflowing at the east entrance," an information officer of the joint command post quickly reported. "But the call only lasted seventeen seconds, and the last sentence was 'The east side has collapsed.' Since then, all fixed communications inside the tunnel have been interrupted."

The cursor on the screen was blinking.

"A white maintenance vehicle, its last GPS positioning signal stopped at a position one thousand one hundred and thirty meters from the west entrance. The truck's last position was further east. As for those two road inspectors, they were originally entering the tunnel from the east entrance to check the water accumulation situation; after the disaster occurred, there has been no echo whatsoever."

The head of the forward joint command post walked up to the structural diagram and pointed a laser pen at a red line.

"The heavy search and rescue team on the west side has tried to enter twice."

"The first time, they pushed forward to eight hundred and seventy meters and found that the large ventilation components at the top of the tunnel had fallen off, with gravel and accumulated water piled on the ground."

"The second time, the assault team pushed forcibly to one thousand and thirty meters. Continuous structural abnormal noises suddenly appeared ahead, and the geological group judged that the main lining of the tunnel was still under stress and squeezing, and secondary collapse could occur at any time. For safety, all personnel were withdrawn."

The spot of the laser pen drew a circle in a section of the map, which was marked in a glaring red.

"The maintenance vehicle is at one thousand one hundred and thirty meters," the person in charge said in a deep voice. "If there is anyone in the car, from the position where our assault team withdrew last time, there is only the last one hundred meters left."

"But the fatal problem lies in this one hundred meters."

The geological expert on the side stepped forward and enlarged another set of complex monitoring curves.

"The mountain is still undergoing slow overall displacement this afternoon, and the concrete lining on the right side of the main tunnel is likely to have been compressed and deformed. Right now, no one dares to guarantee which piece of concrete weighing several tons inside will fall off first."

The head of the command post turned his head and looked at Chen Yan with hopeful eyes: "How far can the machines of your Low Entropy Workshop go in that kind of environment?"

Chen Yan pondered and said: "How far they can go depends on three hard conditions: the extension limit of the communication relay chain, the actual depth of the accumulated water, and the remaining Physics width after the channel deformation."

"If they encounter deep-layer disconnection, can the machines still continue?"

"The preset logic is to stop advancing and prioritize attempting to restore communication in place. If it is confirmed that it cannot be restored, it will autonomously withdraw along the nearest path confirmed to be safe."

The person in charge frowned slightly and said: "Can the logic be modified on site so that after disconnection, it continues to blindly search forward?"

"The code can be modified," Chen Yan looked back at him without yielding, "but we cannot do that."

The tent fell silent for a split second.

Chen Yan lowered his head and quickly swiped out the task page of PG-P01 on the terminal.

"The purpose of the machine entering is not to let itself bravely disappear inside. It must bring back alive the real road conditions, harmful gas concentrations, environmental sounds, and thermal imaging data inside. If it forcibly continues to advance but brings back no data, it has no substantive significance for subsequent rescue planning."

The head of the command post was silent for two seconds and did not insist further.

"Execute according to your safety boundaries."

At this time, the senior underground engineer sent by the client stood in front of the structural diagram and pointed to an inconspicuous thin line on the right side of the main tunnel.

"Everyone pay attention, there is a maintenance channel here."

"Under normal design, there will be a waterproof inspection door between the maintenance channel and the main tunnel every two hundred meters. But after the violent impact just now, the positions of the doors may not all be opened smoothly."

Another accompanying engineer added: "This morning, we followed the search and rescue team to look eight hundred meters ahead of the west entrance. The main structure of the maintenance channel is much more complete than the main tunnel, but the drainage ditch has completely overflowed."

"If a large-scale local collapse has indeed occurred in the main tunnel after one thousand meters, and neither tracks nor people can get through, we can try to let the machine detour from this side maintenance channel."

The geological personnel raised a question: "The cross-section of the maintenance channel is so small, wouldn't it be more dangerous?"

"It is relatively far from the side of the mountain under stress, and a small cross-section also means a small span; it may not have suffered the same fatal structural impact as the main tunnel."

"Just 'may not'?"

"Yes, just 'may not'," the engineer sighed, "because right now, no one has ever entered."

This was also the reason why everyone on site urgently needed these machines.

3:37 PM.

All five hexapod robots had completed unloading.

Rainwater fell on their dark gray engineering shells, flowing down along the anti-slip textures and joint gaps.

They quietly lurked in the mud, waiting to be awakened.

unit 1: As the vanguard, it removed all unnecessary loads, fully equipped with a visible light pan-tilt, a high-precision thermal imager, an array sound collector, and an anti-corrosion gas detection module.

unit 2: The core base station, with three high-power communication relay beacons firmly fixed in the expansion slot on its back.

unit 3: Logistics support, carrying sealed drinking purified water, insulated emergency blankets, rapid hemostatic materials, backup lighting fixtures, and a simple two-way communication terminal on its back.

unit 4: Flank ranger, retaining the exact same full set of search and perception capabilities as unit 1.

unit 5: Heavy-duty standby, staying within the warning line at the entrance, ready at any time to use chassis torque to undertake towing, obstacle clearance, or rescue relief missions.

The rescue personnel on site quickly dispersed around them, making way for a direct passage to the entrance.

The fire rescue assault team began a second heavy check of respirators and demolition equipment in the assembly area behind the tunnel entrance.

Medical personnel pushed the folding stretcher with a rain cover and defibrillation equipment to the muddy ground closest to the warning line.

Several family members of the missing personnel who rushed over upon receiving the news were specially arranged in temporary rest tents further away, cared for by dedicated personnel, and no one was allowed to approach the dangerous entrance.

In the rain curtain, a middle-aged woman wearing a thin coat refused to enter the tent.

She just stood there across the distant warning line, her hands tightly gripping her mobile phone all along.

The screen did not light up.

But she did not put it away either, just stubbornly waiting for a ringtone that might never ring.

Chen Yan only took a distant glance, then forcibly withdrew his gaze and turned all his attention back to the task terminal in front of him.

3:46 PM.

Jiang Lin's signal was connected to the forward command link from the Jiangcheng manufacturing node.

The video screen only occupied a very small area in the lower right corner of the main screen.

"Send the comprehensive map of the site over."

Chen Yan immediately tapped the keyboard and packaged and uploaded the proven safe areas on the west side, the original CAD structural diagram of the tunnel, and the secondary disaster monitoring data just updated by the geological group.

Jiang Lin's gaze swept quickly across the screen and finished reading it shortly.

"The goal of the first stage is only to push forward to the position of that maintenance vehicle," his voice clearly came through, "confirming the vehicle's damage situation, traces left by personnel, and the true channel state ahead. Do not rush to look for the east exit."

The head of the command post frowned and asked: "What if no one is found near the maintenance vehicle at all?"

"Based on the Physics traces left at the site, decide whether to retreat or advance in the next step."

"What if all traces have been washed away by accumulated water?"

"The things the machine can see are not limited to footprints on the ground," Jiang Lin paused for a moment, his tone firm, "but before obtaining firsthand real data from the site, we should not blindly advance."

3:52 PM.

The order was issued.

unit 1 officially entered the tunnel.

Accompanied by the faint humming sound of servo motors, the six metal foot ends stepped into the muddy water at the tunnel entrance one after another. Its pace was steady, and circles of turbid ripples spread to both sides.

The twenty-thousand-lumen high-brightness searchlights in front of the fuselage instantly turned on, like two sharp swords, tearing apart the dim space ahead of the tunnel section by section.

High-definition footage was transmitted back to the command vehicle in real-time.

Scattered on the ground were plastic reflective cone buckets washed down by the current, broken thick cables, and sporadic metal ventilation components fallen from the top.

Near the west entrance, one could still clearly see the messy footprints left by the assault team during their exploration in the morning.

Behind unit 1, unit 2 followed closely at a distance of twenty meters.

unit 3 stopped under the rain canopy at the entrance on standby.

unit 4 and unit 5 remained in a static dormant state.

The first-person perspective footage in the main screen continuously advanced into the depths of darkness.

One hundred meters.

Three hundred meters.

Five hundred meters.

There was no trace of any personnel appearing in the spacious tunnel.

Only the groundwater seeping from the ground surface and the rainwater falling along the cracks continuously beat against the water surface in the darkness, emitting empty echoes.

At six hundred and twenty meters.

In mid-air ahead, a section of heavy metal lighting stand bent and hung down from the top.

The lowest position after the deformation of the lighting stand was less than seventy centimeters away from the accumulated water surface below.

unit 1's front radar instantly scanned out the obstacle.

The control system automatically intervened, and the fuselage slowly lowered.

The six mechanical legs expanded greatly to both sides, and the armor plate on the belly almost hugged the cold water surface.

With a low-lying posture similar to a spider, it slowly and steadily passed through underneath the fractured lighting stand.

"Squeak—"

The irregular metal edges heavily scraped across the engineering plastic shell on top of the fuselage.

A sharp and harsh frictional sound was directly transmitted back to the command post via the pickup.

Inside the carriage, someone subconsciously shrank their neck and leaned closer to the screen.

After unit 1 passed through the Physics barrier, the chassis hydraulic cylinders were re-pressurized, raising the body and continuing to step forward.

At seven hundred and ninety meters.

The depth of the accumulated water ahead increased noticeably.

The black water surface was already approaching the waterproof seal line on the lower edge of unit 1's belly.

"The gas detection probe readings are normal and still within the safe range." Chen Yan stared intently at the screen, reporting the data, "The battery compartment and the seals of all joints are in good condition, with no abnormal alarms."

Eight hundred and seventy meters.

In the image, a huge white cross mark left by the search and rescue team in the morning using waterproof fluorescent paint appeared on the tunnel wall on the right.

[Personnel Exploration Endpoint]

Starting from this white mark, everything in the thick darkness ahead was an unknown domain.

unit 1 stopped in the water for two seconds.

Its front right foot slowly lifted and tentatively landed into the turbid water ahead.

After the chassis force sensor confirmed that the concrete on the ground had no cavities or collapses and could provide sufficient bearing capacity, it withdrew its probe, resolutely stepped across the line, and continued forward.

In the command area, the sound of talking and communication became less and less, leaving finally only the faint current sound of the instruments.

The fire rescue personnel in the distance had completed the third entry preparation, quietly lined up and waited, but not a single person urged the machine to speed up via the walkie-talkie.

Because they knew better than anyone else that in such a blind spot, being a few minutes faster was meaningless.

Once the wrong path was chosen, or a secondary collapse was triggered, all time would truly be lost.

Nine hundred and thirty meters.

On the main screen, a terrifying and obvious dislocation appeared at the top of the tunnel for the first time.

Under the squeeze of the huge mountain pressure, the thick concrete lining on the right had bulged severely inward, covered with cobweb-like cracks.

A large amount of half-meter-square large gravel was piled up on the ground.

A thick iron ventilation pipe originally suspended from the top was abruptly torn off, twisted and straddled across the middle of the road, leaving only a narrow, irregular space of less than sixty centimeters below.

In this kind of terrain, traditional tracked rescue equipment absolutely could not pass.

And human rescuers, even when carrying complete protective equipment and oxygen cylinders, would find it difficult to guarantee passing safely underneath without touching the surrounding structures.

unit 1 executed a low-profile posture again.

The two mechanical legs in front probed into the complex gap.

The two middle legs supported the sinking center of gravity of the body.

The rear two legs gradually folded up, close to the chassis.

Through the alternating force of its six feet, it pushed the entire heavy body piece by piece underneath the obstacle.

Suddenly, a loose small stone detached from the crack at the top and hit the armor on the side of the body with a snap.

A short gasp immediately sounded in the command area.

unit 1 stopped instantly.

Fine-tuning its posture, the six foot ends redistributed the supporting torque.

After the millimeter-wave radar scanned the surroundings and confirmed that the top did not trigger a chain reaction of falling rocks, it slightly moved its joints again and continued to crawl forward.

Thirty-seven seconds later.

Dragging several scratches, the gray machine appeared completely on the other side of the obstacle.

According to preset instructions, unit 2 stopped in the safe area in front of the obstacle.

Chen Yan marked the coordinate point on the 3D map: "unit 2, prepare to deploy the first relay beacon."

In the image, the mechanical fixing lock on unit 2's back clicked open.

The robotic arm extended and placed a blue-flashing repeater on a relatively high concrete platform.

On the signal waveform diagram, the communication bandwidth that had begun to attenuate instantly rose and maxed out again.

Receiving the confirmation signal, unit 1 continued to push deeper.

Four twenty-three in the afternoon.

One thousand and ninety meters from the west entrance.

At the edge of the high-brightness searchlight's view, a dazzling yellow suddenly appeared.

That was the first item belonging to the missing personnel found after entering the unknown area.

A yellow hard hat with reflective strips was turned upside down in the turbid accumulated water.

The brim was stuck on the broken edge of the side drainage ditch, and it had been washed back and forth by the turbulent muddy water.

unit 1 slowly approached and lowered the pan-tilt.

The camera zoomed in.

The suspension strap inside the hard hat was intact, and no bloodstains were found.

The paint spray code on the side showed that the serial number belonged to the routine maintenance team.

The head of the command post immediately turned their head: "How far is it from where their vehicle was parked?"

"Thirty-nine meters." Chen Yan calculated quickly.

The machine crossed the hard hat without hesitation and continued forward.

More than ten seconds later, a huge white outline finally emerged bit by bit from the heavy darkness.

That was a white double-cab engineering maintenance vehicle.

The front of the car faced west, apparently attempting to turn around and escape when the disaster struck.

But the right side of the vehicle body crashed heavily against the tunnel wall, and the front windshield had completely cracked under stress, covered with cobwebs.

The doors on both sides were wide open, and when the flashlight beam swept across, the driver's seat and the back row were empty.

The yellow warning light on the roof was still flashing faintly.

unit 1 carefully circled around the perimeter of the vehicle.

Four fluorescent reflective vests were scattered haphazardly on the cab seats.

Opened tool kits, a few bottles of unopened drinking water, and walkie-talkies were scattered on the floor of the back row.

Below the car door, in the mud where the water flow was relatively gentle, the high-definition camera captured several dark traces that had been washed very faint by the accumulated water.

"Magnify the image, switch filters." Chen Yan ordered.

Spectral analysis showed that it was not large-area spray bleeding.

It looked more like bloody handprints left behind when someone got injured, placed their bloody hand on the edge of the car door for leverage, and then left.

The underground engineer sent by the client had been staring closely at the corner of the screen, and suddenly pointed at the image: "Turn unit 1's camera to the right, quick."

Chen Yan pushed the joystick, controlling the pan-tilt to turn to the rear right of the vehicle.

On the wall blocked by the rear of the vehicle, a metal maintenance door impressively appeared.

The door lock had been violently smashed open by external force.

In the semi-dry mud at the threshold, several messy but very clear friction marks were left.

The height of one of the marks was very low, and the soil was dragged into a long, flat gully.

"Someone was injured and could not walk, and was dragged hard through this door." The engineer said with certainty.

The geological personnel immediately pulled up the design structural drawing of that section.

"This maintenance door leads directly to the narrow maintenance passage on the right."

"Entering from this door and walking two hundred and seventy meters east, there is an independent drainage pump room designed for flood control."

"If you continue walking forward, you will pass three identical maintenance doors along the way, and finally reconnect with the main tunnel at the end of the tunnel."

The head of the command post frowned and asked: "In front of the main tunnel, can people still walk?"

Chen Yan controlled unit 1's high-intensity light to shine directly to the east of the engineering vehicle.

The road no longer existed.

A large patch of huge components collapsed like a small hill, completely cutting off the main tunnel.

Hundreds of thousands of tons of concrete blocks, twisted giant ventilation pipes, sharp gravel, and torn thick steel bars were intertwined and piled together, and not even a gap for a mouse to drill through could be seen.

The road in the main tunnel ended here, becoming a dead end.

Only the smashed maintenance door of the maintenance passage on the side was the only gap where survival was possible.

"Let unit 1 enter the maintenance door!" The head of the command post resolutely gave the order.

Chen Yan looked up at Jiang Lin in the lower right corner of the screen.

"After entering the thick-walled metal door, how much will the signal attenuate?" Jiang Lin asked.

"There is a compressive steel bar mesh blocking behind the door, and it is expected that the signal strength will instantly drop by more than two levels above the main tunnel." Chen Yan replied truthfully.

"Have unit 2 follow up immediately and push all the way to the position of the maintenance vehicle."

Chen Yan reminded: "If unit 2 moves forward, it must cross the first top dislocation danger zone at nine hundred and thirty meters just now."

"It is fine, let it pass."

Chen Yan took a deep breath and said: "Understood, unit 2 is following up, and the second relay beacon is ready to be placed on the roof of the engineering vehicle."

The command was issued via radio waves.

unit 2 in the rear started immediately, accurately replicating the puddle that unit 1 had waded through just now, safely crossing the dislocation obstacle, and moving forward quickly along the path confirmed to have no fatal traps.

Five minutes later.

The robotic arm raised, and the second blue relay beacon was firmly adsorbed on the roof of the white engineering vehicle.

The fragile signal bridge between the main tunnel and the maintenance passage was re-connected and established.

Four thirty-four in the afternoon.

Supported by a stable signal, unit 1 turned sideways and squeezed into the maintenance door of the maintenance passage.

The space inside was even narrower and more oppressive than indicated on the original design drawings.

The drainage ditch on the left had long lost its function, and the overflowing sewage crossed the ditch, continuously flowing to the low-lying area in the west.

Various cable pipelines and distribution control boxes were densely fixed on the wall on the right, and some metal box doors had fallen off in the vibration, revealing messy wire ends inside.

The machine had to adjust its gait, retracting the three mechanical legs on the right more compactly, walking almost close to its own belly.

Every few meters it moved forward, it had to use radar to predict and avoid sharp concrete fragments on the ground and cables hanging from mid-air that might be live.

The high-brightness illumination lamp swept across the walls on both sides of the passage inch by inch like a brush.

On the walls, several fresh scuffs with muddy water appeared.

In a puddle, a canvas work glove stained with yellow mud was also discarded.

The traces were conclusive.

The people they were looking for had indeed escaped deeper from here.

Four forty-one in the afternoon.

unit 1 moved forward slowly, and a Y-shaped fork suddenly appeared ahead.

The left passage went slightly upward, leading to the higher-elevation drainage pump room.

The right passage extended in parallel, continuing deep eastward along the direction of the main tunnel.

In the center of the fork, the accumulated water on the ground was deeper, and the muddy water had been stirred up, making it impossible to visually distinguish any footprints or dragging marks.

The clues broke here.

unit 1 stopped steadily in the accumulated water in the center of the fork.

"Silent monitoring mode activated." Chen Yan gave the command on the terminal.

All servo motors of unit 1 instantly reduced power, the cooling fans stopped running, and its own operating mechanical noise was reduced to the lowest threshold.

The 20,000-lumen illumination lamp in front was also dimmed accordingly to reduce environmental interference caused by light pollution.

The high-sensitivity array pickup was turned on at full power.

In the dim and narrow maintenance passage, instantly only the monotonous sound of dripping water and the rustling sound of sewage flowing in the distance remained.

Three seconds.

Five seconds.

Ten seconds.

There was no sound belonging to human activities.

In the command post, someone's breathing became rapid, and they could not help guessing in a low voice: "Did they not go to the pump room and instead went straight along the right side to the east entrance?"

As soon as the voice fell, on the audio analysis waveform diagram in front of Chen Yan, a small and short rise suddenly appeared.

Thud.

The sound was very muffled.

A full six seconds apart.

The audio waveform jumped again.

Thud.

Another long six seconds.

The third sound.

Thud.

The sound was very faint, and if it were not for algorithmic noise reduction, it would almost be covered by the sound of water.

But this definitely did not sound like the muffled sound of rocks naturally falling under gravity, nor did it sound like random bursting sounds produced by metal pipes due to thermal expansion and contraction.

Because it maintained a nearly deliberate six-second fixed interval.

This was a logic that people would only possess when struggling to survive.

The head of the command post suddenly stood up from the chair, supported hands on the table, and face almost stuck to the front of the screen.

"Which direction did the sound come from?"

Chen Yan's hands danced on the keyboard, re-partitioning and calculating the phase difference returned by the three sets of high-sensitivity pickups.

"Left." Chen Yan confirmed loudly, "It is the direction of the drainage pump room."

"Give them a response, right now." Jiang Lin's calm voice immediately cut into the communication link.

Receiving the order, unit 1's dimmed high-intensity illumination lamp instantly burst into dazzling white light, flashing three times consecutively at a fixed frequency toward the left passage leading to the pump room.

Immediately afterwards, the waterproof external speaker on the top of unit 1 emitted electronically amplified human voices.

"This is the provincial joint rescue team, this is the rescue robot."

"If you hear the sound, please knock on an object three times consecutively."

The broadcast was complete.

The maintenance passage fell back into dead silence.

Everyone did not even dare to breathe, staring fixedly at that audio waveform line.

Five seconds.

Ten seconds.

Fifteen seconds.

Completely flat, no response.

Those exhilarating three knocks just now seemed to be just some cruel coincidence caused by geological changes.

Chen Yan clenched his teeth, staring at the screen without blinking an eye.

Just at the twentieth second, just when someone was about to sigh——

In the distance, a burst of metal knocking sounds that was messy and somewhat crazy suddenly erupted.

Clang!

Clang!

Clang!!

Then, it seemed that the person lost control of their emotions, followed by two more rapid and chaotic impacts.

There was someone inside, a living person!

A suppressed cheer burst out in the temporary command area, and immediately, all the battle-hardened rescuers moved into action at almost the same time.

The head of the headquarters grabbed the walkie-talkie: "Medical team, immediately bring all first-aid equipment and prepare to provide support at the entrance of Channel 1."

"Fire Team 1, immediately re-evaluate the manual entry conditions for the maintenance channel based on the explored map!"

"Geology team, immediately pull out the rock layer monitoring point data for the area directly above the pump house separately, and keep an eye on the deformation amount there."

At this moment, Chen Yan directly pushed down the joystick, made unit 1 turn left, and drove into the passage leading to the pump house.

Because of geological squeezing, the width of this section of the road leading to the pump house had narrowed to less than eighty centimeters.

After advancing thirty meters ahead, a thick overhead water supply pipe rack collapsed severely, completely sealing off the upper half of the passage.

The pipes and broken concrete blocks were intertwined, and at the very bottom of the obstacle, an irregular triangular gap was barely left.

Lidar calculation: The narrowest position was only forty-eight centimeters.

"Lower the chassis to the limit position."

All hydraulic suspensions of unit 1 dropped to the lowest point, and its belly rubbed almost against the mud.

Its right front foot was the first to probe into that cramped gap.

The feedback from the ground was exceptionally poor.

A layer of rotten mud and sand, soaked extremely soft due to long-term water immersion, sank severely as soon as the first metal foot tip bore weight and landed, and the muddy water instantly swallowed the ankles.

The machine's algorithm immediately determined that the bearing capacity was insufficient, and the servo motor reversed.

It decisively withdrew its front foot, shifted a dozen centimeters to the left horizontally, and re-searched for a landing point with broken bricks.

For the second probe, the supporting force feedback was stable.

The fuselage began to squeeze into the gap bit by bit with difficulty.

The edges of the severely deformed metal pipe rack at the top inevitably brushed heavily against the outer shell on the back of the machine, making a long series of teeth-aching sharp frictional sounds.

Suddenly, the right rear foot of unit 1 lagged, tightly entangled by a steel-core cable that had long been broken and frayed hidden underwater.

If pulled forcibly, it was very likely to snap the exposed sensor harness on the leg.

The machine immediately stopped its forward movement, and its right rear leg contracted in reverse, trying to untangle itself.

The steel wires of the cable were extremely tough and did not loosen.

The ankle joint of the right rear foot began to rotate slowly, changing the physical angle, pulling outward bit by bit from that dead knot like solving interlocking rings.

Twenty-one seconds later.

unit 1, having broken free from the constraints, finally crossed the pipe rack obstacle covered in mud and scratches.

The road ahead began to rise slightly.

The accumulated water gradually became shallower, revealing the damp ground.

And the metal knocking sound full of the desire to survive coming from behind the door also became clearer and clearer.

Four-fifty-two in the afternoon.

unit 1 arrived at the outer corridor of the drainage pump house.

The originally sturdy explosion-proof and flood-prevention pump house door had now undergone severe deformation under huge external pressure.

The heavy metal door panel caved inward terrifyingly, the door axis at the bottom broke, leaving only a narrow and long gap less than thirty centimeters high below.

At this height, even if unit 1 dropped to its chassis limit, it would be absolutely impossible to crawl directly inside.

Moreover, the line of sight of the high-precision thermal imager was completely blocked by the heavy metal door panel and the load-bearing walls on both sides, and Chen Yan could not clearly see any human thermal source outlines inside on the screen.

However, human rapid breathing and suppressed groans were already close at hand.

unit 1 parked steadily on the open space in front of the door, and the camera aimed at that gap.

Chen Yan pressed the talk button, trying to slow down and flatten his voice: "People inside, can you hear me?"

A vague shout immediately came from behind the door.

The sound was too light, completely mixed in the leaking water sound after the machine inside the pump house broke, making it impossible to distinguish the specific content at all.

Chen Yan pushed the speaker output volume on the terminal directly to the maximum.

"This is the Provincial Joint Rescue Team."

"Please speak as loudly as possible and state your number of people, as well as the initial condition of the wounded."

It suddenly became quiet for a moment behind the door.

It seemed that the people inside were trying to save their remaining physical strength.

Subsequently, a hoarse and cracked man's voice came out intermittently from beneath the door crack.

"Hear... can hear..."

In the headquarters tent, everyone stopped what they were doing at this very moment.

"We... we have four here..."

"Four people... are all still alive..."

The information officer responsible for compiling the list of the missing abruptly closed his eyes and took a deep breath.

Turning around, he picked up a red pen and heavily marked four checkmarks symbolizing life next to the names of the four maintenance workers on the whiteboard.

The knuckles of Chen Yan's fingers turned white from tightly gripping the edge of the terminal.

"Are there any seriously injured people?"

The man behind the door gasped in pain for a few breaths of cold air.

"One person... leg is pinned by a large stone and cannot move... another one, got a cut on the head and has been bleeding..."

The man's voice carried an undisguisable fear: "There is water in our room... water... the water is still rising..."

The chief medical officer on the side snatched the backup microphone next to Chen Yan and quickly accessed the communication channel.

"I am the head of the medical team. Are the injured personnel still conscious now? Can they speak?"

"Conscious... but very weak."

"Is there massive pulsating bleeding from major arteries?"

"No... rags and clothes have already been tied tightly."

"Listen up, do not move that brother whose leg is pinned casually now to prevent secondary crush syndrome. You guys try to stick together to keep warm, and from now on talk less to conserve physical strength. Our demolition rescue personnel have found the way and will be here soon."

A burst of chaotic noise came from behind the door.

It seemed someone finally couldn't withstand the huge psychological pressure and cried softly in the dark.

There were also companions patting him weakly, advising him to hold back his tears and voice.

The head of the joint headquarters walked quickly behind Chen Yan, lowered his voice, and asked with an extremely serious tone: "What about the other three people?"

Chen Yan nodded and turned on the speaker again.

"Brothers inside, listen up. There are still three missing personnel outside, two patrollers and one driver. Have you seen them before or after the cave-in?"

The answer from behind the door came hard and long after.

"Seen... seen those two patrollers..."

"After the first hit of the cave-in, they passed by and did not enter our pump house to hide."

"They said... said on the east side, another truck was buried... they were going to the east to look for people..."

"At that time, rocks were flying everywhere... we... we couldn't hold them back..."

In the headquarters, the eyes of all experts simultaneously shifted from the screen and fell on the long structural diagram on the wall.

The drainage pump house was not the end point.

Continuing eastward along the maintenance channel, this gloomy passage could extend for more than six hundred meters, leading directly to the deepest part.

Two dedicated road patrollers.

Plus a truck driver whose life or death was unknown.

Exactly three people.

Four maintenance workers had been snatched back from the hands of the Grim Reaper.

But the remaining three names were still in the deepest and most dangerous area on the map.

Four-fifty-seven in the afternoon.

unit 3, starting.

It stepped out from under the safety rain canopy at the western tunnel entrance.

The special material rack on its back had been frantically re-counted by logistics personnel one minute before departure.

Pure drinking water.

Polymer thermal blankets.

Rapid hemostatic bandages and antibiotics.

High-intensity emergency lighting flashlights.

A fully charged military two-way communication terminal.

The dangerous route of more than 1,100 meters along the way had already been paved by unit 1 in front, generating a complete high-precision 3D point cloud map.

This time, unit 3 no longer needed to cautiously test the depth of the accumulated water, nor did it need to scan whether steel bars would fall overhead.

It would raise its speed to the maximum and deliver supplies into the pump house at the fastest speed.

And unit 2, like a loyal guard, was pinned at the commanding height next to the maintenance vehicle, using the antenna on its back to maintain this fragile life communication chain.

unit 1 quietly stayed outside the deformed door of the pump house, illuminated the door gap with a high-intensity light, and maintained continuous voice soothing contact with the four trapped people inside who had endured more than a dozen hours in the dark.

Finally, unit 4, which had been standing by at the cave entrance, carried the last remaining high-power relay beacon in the camp on its back.

Its camera turned eastward, ready to continue searching for the traces of the last three people along the maintenance channel toward the deeper place where even unit 1 had never set foot.

At the same time.

Wearing heavy demolition equipment and respirators, the first team of fire special service command re-planned the personnel assault route for entry based on the centimeter-level 3D topographic map sent back by the robots.

A death passage that no one dared to step into previously due to unknown fear was clearly marked with all dangers on the electronic screen for the first time.

Where there was waist-deep accumulated water.

Where there were rickety falling components.

Where oxygen tanks had to be removed to crawl through.

Where must never be touched, otherwise secondary collapse might occur.

Every trap had already turned into coordinate points on the screen.

The head of the headquarters stared at the map exchanged with the machine's scratches, grabbed the walkie-talkie, and the voice was as cold and hard as steel.

"Fire Special Service Team 1, enter the maintenance channel from the western maintenance door. First target: Drainage pump house, execute demolition and rescue."

"Team 2 establish a safety transfer station at the location of the engineering vehicle and stand by at all times."

"Everyone pay attention, all of you, walk stepping on the footprints just walked by the machine, do not touch the deformed lining on the right side of the main tunnel."

The rain was still falling, washing the surrounding soil even muddier.

Outside Qingya Tunnel, the first personnel assault team composed of flesh and blood finally crossed the yellow cordon and plunged headlong into the darkness.

The equipment they carried on their backs was much heavier than those carbon fiber legs of the machine.

Nor could their footsteps flexibly approach the complex and rugged ground like the six joint-compensated mechanical legs.

But this time, what spanned ahead of them was no longer a desperate dark fog.

Because on this dead end, there was already a bloodless vanguard who had completely trodden through it for them once.

Chen Yan rubbed his dry and sore eyes, and when he raised his head, through the transparent plastic window of the command tent, he happened to see the middle-aged woman in the distance who had been stubbornly standing in the rain, tightly holding her mobile phone with both hands.

She was being supported by two female staff members, walking toward the medical tent.

According to discipline, before people were truly rescued, no one would explicitly tell her the specific result inside.

But she was not stupid.

Her bloodshot eyes had already guessed something from the action rhythm that suddenly erupted across the entire camp in the past dozen minutes.

"Did... did you find them?"

When passing the outside of the command tent, she suddenly stopped and grabbed the arm of the staff member beside her.

The staff member held her trembling shoulders with heartache and nodded.

"Four survivors were found inside the pump house, and people are going in to rescue them now."

The woman's lips trembled violently.

She opened her mouth, panting heavily, and her tears instantly mixed with the rainwater on her face.

Then she lowered her head and used stiff fingers to unlock the mobile phone in hand that had long been soaked by rain. Because of excitement, her fingers swiped the wrong password twice in a row, before finally dialing a number she didn't know who was for, squatting in the mud, and crying loudly.