The Pressure Sweep

How many meters of cast-iron conduit lay between the algae sumps of Sub-deck 14 and the safety of Vault 4B before the overseer's dogs sealed the vertical risers? Levmir wedged his shoulder against the raw basalt behind Trench 6, feeling the tremor of heavy patrol boots through the ceiling plates. He pulled the antique bronze bypass key from his coat, needing clean passage into the drainage shafts before Kordov cut the mid-deck power grid.

The key had six offset square lugs, worn smooth by five decades of sulfur grease. Levmir slotted the shank into the dog-latch of the secondary ballast riser. The brass plug fought the turn, frozen in its seat by hardened mineral deposits. Levmir set the heel of his pipe wrench against the cross-pin and struck the handle with his palm.

Metal gave with a dry snap. Rust flakes dusted his knuckles as the hatch dog swung clear.

He squeezed through the oval aperture feet first. Cold air drafted upward from the ballast vents, smelling of stale nitrogen and iron filings. He pulled the plate shut until the latch settled into its groove, leaving only a hairline crack against the glare of the hydroponic work lamps.

Ten centimeters above his head, the expanded-metal floor grating vibrated.

"Every line," a voice boomed from the upper catwalk. Kordov's vocalizer carried the low, synthetic rasp of an industrial rebreather tuned for thin air. "The thermal surge peaked at eighty kilowatts across the primary loop. Nothing dumps that much heat into the hull radiators without leaving a signature in the return manifolds."

"Sir, the whole sector is running hot," a younger voice answered, shaking beneath the hum of ventilation scrubbers. It was Grigori, the shift tech from the central monitoring station. "The mash vats on nine cycle constantly. If we throttle their circulation to calibrate the sensors—"

"If we lose the radiators, we freeze," Kordov said. The enforcer's heavy boots clanged against the steel treads, stopping three meters from the vent shaft. "If someone bridged the sealed founding core, they breached Cooperative quarantine. Check every junction box from here to Sub-deck 8. Break the security seals if the bolts are corroded. Anyone caught without a signed maintenance slate goes to the airlock muster."

Levmir crouched in the dark slot between the structural ribs. His spine pressed against a four-inch overhead line insulated with decaying rock wool. The pipe thrummed with a steady, rhythmic pulse: the spent mash wash from the secondary fermenters, carrying sixty-five-degree brewer's dregs down to the bio-filtration beds at three bars of hydrostatic pressure.

He slid his thumb along the pipe wall until he felt the square head of a manual blowoff valve.

The bronze casting belonged to the founding era, installed when line clearances required mechanical override before automated telemetry was wired into the decks. A lead tamper wire still threaded through the locknut, but forty years of acidic condensate had eaten the wire down to brittle gray oxide.

If he stayed in the trench, Kordov's sweep team would reach the mid-deck interchange within four minutes. The riser ahead narrowed into an open junction where two armored sentries already guarded the maintenance hoist. Running meant walking into their flashlights.

Levmir measured the valve body against the reach of his twelve-inch wrench. The discharge spout pointed straight through the floor grating into the center of the walkway. A sudden release of ninety liters of fermenting slag wash would flood the corridor with foul, boiling sludge, shorting the battery packs on the portable scanners and triggering the localized fire sensors.

The choice took half a breath: lose the position now, or turn the brewery's waste into an obstacle.

He clamped the wrench jaws onto the square nut. His muscles tightened against the lever arm, feeling the torque build in his shoulders. The old threads groaned under the strain, then broke loose with a shrill squeal of tearing metal.

Levmir spun the valve stem two full turns and threw his weight backward into the lower crawlway.

The pipe screamed. Pressurized slurry hit the deflection plate with the force of a pneumatic hammer. A scalding torrent of gray, bubbling dregs erupted through the grating, atomizing into a thick cloud of sulfurous steam. The wash splashed across the catwalk plates, hissing against the hot housings of Kordov's diagnostic carts.

Shouts cut through the roar of escaping liquid.

"Rupture!" Grigori yelled, his boots slipping on the slick metal floor. "Main line blowoff! The slurry line popped its seat!"

"Seal the junction!" Kordov roared. The thud of his magnetic boot plates lost traction on the oily sludge. "Kill the pump feed from Sub-deck 10!"

"I cannot reach the shutoff!" the junior tech screamed back. "The deck is covered in boiling wash! It is burning through my boot seals!"

Levmir moved beneath the cover of the spray. The air in the trench turned swampy and thick, smelling of sour yeast and cooked iron. Slurry dripped through the mesh overhead, splattering across his leather coat, but the thermal blanket in his jacket lining turned the heat away from his skin. The scalding sludge had already coated Kordov's armored greaves; the ceramic composite plating would require two hours with a wire brush and solvent tank to strip clean of the sticky organic residue.

Levmir climbed up through the secondary ballast riser, using the bronze key to slip through the intermediate baffle at Sub-deck 11. He bypassed the main corridor entirely, traveling the unmonitored drainage conduit toward the outer rock wall.

Five minutes of rhythmic scrambling brought him to the intake plenum of Sector 4. The air here was cooler, dry and faintly sweet with the familiar aroma of active Spirka cultures. He popped the inspection hatch into the lower corridor of Sub-deck 9 and stepped onto the dry basalt floor, his boots leaving faint, evaporating smudges of yeast water.

Vault 4B stood thirty paces down the hall, its reinforced door frame bearing the yellow wax mark from the morning's triage team.

Levmir unlatched the heavy hatch dog and stepped inside the brewery. He checked the mechanical gauges mounted on Mash Vat Seven's jacket. The vessel registered 38.1 degrees Celsius. The glycol line pressure held firm at 3.1 bar. Inside the vessel's dark iron belly, the bronze Year 12 token rested untouched beneath two feet of acidic magnetite silt.

He drew his service rag and wiped the sour condensation from his forearms. He turned back to dog the heavy hatch from within.

Before his hand touched the iron, the overhead warning sirens cut through the bulkhead with three sharp, piercing chimes.

The yellow emergency lights in the corridor strobed into solid crimson. The station-wide public address system clicked open, carrying Kordov's voice, devoid of inflection and magnified by the full power of central command.

"All personnel, this is Overseer Security," the broadcast declared, the words echoing through every vent, conduit, and living compartment across Zhelezkova. "Unauthorized thermal extraction has compromised primary radiator stability. By decree of the Cooperative Council, Sector 4 is under immediate quarantine. Any industrial vat or fermentation bay showing unlogged thermal dissipation will be purged directly into hard vacuum at the end of the current shift. You have three hours to present operational logs to the central triage dock."

The speaker popped and fell silent.

Levmir let his hand drop to his side. The iron door of Vault 4B stood between him and three metric tons of dying calories, and the station had just started counting down the minutes.