81: Chapter 81 Rust Coordinates and Nerve Freeze

The darkness of Tunnel B-17 possessed a physical weight.

Lin Yuan leaned against the peeling concrete wall, his knuckles pressed against his temple where a neural burn, synchronized with his brother's, throbbed. The zeroing out of Promethium reserves meant THRONE-01's cooling system was paralyzed; the temperature of the liquid metal neural network was burning backward through the bio-fused junctions into Lin Chen's spinal cord. He could smell it—that burnt stench of ozone mixed with rust seeping from the gaps in his brother's left arm joint, like a red-hot iron dipped into sewage.

Camilla lay on a drainage grate three meters away, her body undergoing tonic spasms every ninety seconds. Neural necrosis from the T7 to T12 segments was climbing upward, and the cruelty of wasteland medicine was laid bare at this moment: no inhibitors, no replacement consumables, only a countdown. Two hours and seventeen minutes—that was the limit Lin Yuan estimated based on her pupil dilation and muscle rigidity.

"Backup energy." Lin Yuan fished out a fingernail-sized Promethium crystal from a compartment in his breastplate—the last of their strategic reserves, originally intended to power an Emergency Phase Distorter for extraction. "Parsing the stc fragment takes ninety seconds. The energy signature will reveal our position to The Mother at the top of the tunnel."

Lin Chen looked up. Within the sockets of his dark red exoskeleton, the liquid metal's flow was as dim as dying embers. Coolant dripped from his left elbow joint, pooling into a small, viscous silver puddle on the ground. He didn't speak, but through neural empathy, Lin Yuan received a data fragment—an image from the Warhammer memory bank: a warrior of the Seventh Legion carrying a wounded brother through an acid rain swamp, no survival probability calculated, only a rust-scented obsession with the words "For the Primarch."

"Risk factor: forty-seven percent," Lin Yuan recorded in his military log, the pen nib tearing the paper. "Moral bankruptcy coefficient: one hundred percent."

He crushed the Promethium crystal, injecting the energy into the stc fragment left behind by the Scavengers.

The fragment hovered three centimeters above his palm, the Gothic inscriptions on its surface beginning to glow. It was a dark gold hue that resonated with the THRONE-01 armor, like an ancient gene being awakened. Analysis ripples spread outward with Lin Yuan at the center. Suddenly, a tooth-gritting grinding sound came from the concrete at the top of the tunnel. The Mother had sensed it; the thing was using bio-metal claws to tear open the ventilation ducts, and a low-frequency hum pressed in from all directions like the wingbeats of some giant insect.

"Forty seconds." Lin Yuan stared at the 3D projection emerging from the fragment's surface—a three-dimensional structure of the deep layers of Sector B-17. "Coordinates confirmed: Sector-B17-Theta, pre-war Adeptus Mechanicus bio-lab, depth: three hundred meters."

Camilla's spasms suddenly intensified. She bit down on her forearm to prevent herself from screaming, the sound of teeth sinking into muscle exceptionally clear in the tunnel. Lin Yuan knelt by her side and pulled out the last half-vial of potent anesthetic—a pre-war relic scavenged from a Scavenger's corpse, the label reading "Neural Blockade Grade."

"No." Camilla released her blood-stained teeth, her voice sounding like it was ground out of sandpaper. "If I take this, I'll fall asleep. People who are asleep have no value; you'll leave me here."

She used her fingers to quickly sketch a defensive layout of the Scavenger outpost on the dusty ground. Her fingertips trembled, and blood seeped from under her nails, but every stroke was as precise as if measured with a ruler. Lin Yuan looked at the map and realized it was the internal structure of the Scavenger's core forbidden zone, completely overlapping with the Adeptus Mechanicus lab coordinates pointed to by the stc fragment.

"Rustnail treats that place as a holy site." Camilla coughed up a mouthful of blood, the foam containing the grey-white tissue fragments characteristic of neural necrosis. "Medical pods exist, but they've been converted into traps. No one who goes in ever comes out."

Lin Chen suddenly stood up, his dark red exoskeleton emitting an overburdened metallic groan. He walked to Camilla's side. At his left arm joint, brownish-black patches began to surface on the dark red exoskeleton, looking like dried blood mixed with rust. The machine spirit was screaming; Lin Yuan heard it through empathy. THRONE-01's self-protection protocols were alarming, warning that lending neural resources would lead to irreversible biological corrosion.

"What is he doing?" Camilla stared at the younger brother's movements, her pupils contracting.

"A Seventh Legion tactic," Lin Yuan's voice was tight. "Neural sharing."

Lin Chen pressed the palm of his dark red exoskeleton against the back of Camilla's neck, the surface projection point for the T7 segment. The liquid metal neural network breached the skin surface, establishing a temporary bridge with Camilla's neural dendrites. This wasn't a system-authorized medical procedure; it was a savage application of the machine spirit-bio-fusion state. The younger brother was using his own neural signals as a cryo-medium, forcibly blocking the diffusion path of the necrosis within Camilla's body.

Camilla's scream was cut off in her throat. The moment the pain suppression took effect, her body went limp, but her eyes became clearer. She felt a cold torrent surge in from the back of her neck—it wasn't the numbness of anesthesia, but something more primal, as if someone had dipped her nerve endings into liquid nitrogen.

"Synchronization rate: sixty-three percent." Lin Yuan watched his brother's left arm joint, where the brownish-black corrosion was spreading from the elbow to the wrist. The dark red armor looked like a corroded ancient shield. "Safety threshold exceeded; THRONE-01's mechanical integrity is being lost."

Lin Chen did not stop. Warhammer memory fragments burned deep in his consciousness—data scraps about "For the Brothers," heavier than any machine spirit logic. Coolant overflowed from his nostrils, the dark silver liquid dripping onto Camilla's collar and instantly freezing into ice crystals.

Camilla lost sensation in her lower limbs. Permanently. She could feel the neural necrosis frozen at the T12 segment, as if someone had used red-hot wire to weld shut a breached dam, but the cost was that the downstream would be forever dry. She tried to move her toes; only void answered her.

"Coordinates." Lin Yuan grabbed the map Camilla had drawn and overlaid it with the STC projection. "The Adeptus Mechanicus lab overlaps with the Scavenger forbidden zone. The medical pods are a trap, but they're also the only place with pre-war neural repair technology."

The concrete at the top of the tunnel suddenly exploded. The Mother's bio-metal claws pierced through the ceiling, flailing five meters away from them. The thing had no eyes, only a ring of sensory organs, all of which now turned toward the yet-to-fade dark gold light of the stc fragment. It had found them; the energy fluctuations were like a blood-scented beacon.

"It's coming down." Camilla tried to prop herself up, but everything below her waist was just dead weight. "Go. I'll provide fire support."

Lin Yuan closed his military log, writing on the latest page: "Camilla. Roster Change: Tactical Core Member - Permanent. Not a temporary collaborator, not a consumable asset. Based on shared trauma and survival needs, establishing a three-person squad command hierarchy."

He stuffed the notebook back into his breastplate, his right hand gripping a Vibrating Blade while his left grabbed the stc fragment. The coordinates on the fragment's surface were already seared into his retina: B17-Theta, three hundred meters deep, the intersection of the Adeptus Mechanicus ruins and the Scavenger forbidden zone.

"No." Lin Yuan used the tip of his blade to hook Camilla's backpack strap and tossed it to his brother. "We aren't going to the medical pods. We're going to the Adeptus Mechanicus lab to find the source, then we'll come back and dismantle Rustnail's trap."

Lin Chen hoisted Camilla up with his dark red exoskeleton, his movements clumsy but steady. The rust on his left arm had already covered the entire elbow joint, the brownish-black patches looking like a scar against the dark red base. Camilla slumped over his shoulder, still clutching the half-finished map, the pencil lead broken between her fingers.

The Mother completely tore open the ceiling, its bio-metal body squeezing into the tunnel. Acid dripped from its mandible, corroding the iron rails on the ground. Lin Yuan turned and moved toward a maintenance shaft deep in the tunnel, which led to the deep structures of B-17 and the forbidden zone indicated by the stc fragment.

"Lin Yuan," Camilla suddenly spoke, her voice carrying a strange calmness due to the neural freezing. "If I slow you down, leave me behind. That's part of the new protocol."

"Part two of the new protocol." Lin Yuan didn't look back, his Vibrating Blade tracing a pale blue electric arc in the darkness. "No one gets left behind. For collective survival, we sacrifice individually, but no one is abandoned."

They rushed into the metal ladder of the maintenance shaft, Lin Chen's rusted left arm scraping against the handrail with a piercing noise. The Mother let out a first charging shriek behind them, but Lin Yuan had already memorized the coordinates—not the location of the medical pods, but somewhere deeper: the bio-lab left by the Adeptus Mechanicus, where the secrets of the stc fragment were hidden along with taboos the Scavengers dared not touch.

The military log was in his pocket, the ink of that newly written line not yet dry. Camilla's lower limbs hung from his brother's arms like a piece of shed equipment, but her fingers were still moving, lightly tapping on Lin Chen's back to transmit the frequency codes of the Scavenger patrols.

Above the tunnel, The Mother's humming suddenly paused for a second.

Then, an even more violent sound of tearing metal surged from all directions.