Mina didn't look back.
That was how Isaac knew not to.
They hit the turn into south imaging at a run, shoes slipping on polished tile and rubber edging, the whole corridor breathing red from emergency strips low along the wall. The painted cartoon fish and stars on pediatric doors looked obscene in that light. Jadah stayed on Isaac's arm by force and refusal both, blanket-wrapped hands clenched around his sleeve hard enough to wrinkle the fabric.
Behind them, from back where the dark had swallowed the bend, something struck something else hard enough to ring through the floor.
Not a gunshot.
Not a body hitting a wall either.
Bigger than that. Cleaner. Like force meeting force and both of them human enough to hate it.
The young voice laughed once.
Then choked off.
Isaac didn't turn.
Good instinct, because a second later Mina snapped, "Eyes front."
They took the next corner so fast Ren nearly clipped the case against a painted handprint mural. The hall ahead ran straight to a red EXIT sign over a push-bar door marked SOUTH STAIR 3. Two doors on the left. One on the right. All shut. All dark except for a pulse of generator light under the frames.
Isaac's thread jerked.
Not behind.
Not ahead.
Left.
"Wait."
Mina was already at the stair door. "No time."
"Left."
That got her.
Only because the word came out wrong. Not louder. Worse. Certain in a way Isaac himself didn't trust.
Ren stopped with one boot planted, half turned toward the stair door, half toward him.
"What left."
He pointed at the second door on the left.
No sign. Just a narrow rectangle of reinforced glass and a plastic placard with the lettering half peeled off: CLEAN SUPPLY / MRI SOUTH.
The thread in his chest pulled there once, hard, then flattened.
Two beats later, the stairwell door exploded inward.
Not open.
Inward.
The crash bar snapped off its mounts and shot across the corridor at throat height. Mina ducked on instinct. It hit the opposite wall hard enough to crater plaster and bounced once screaming over tile.
If they'd been stacked at the exit, it would have taken someone's head off.
Nobody spoke for half a second.
Then Mina slammed the supply room door open. "Inside."
They piled through.
It wasn't a supply room anymore. It had been stripped down to plastic shelving, boxed gowns, bandage packs, diapers, sealed tubing, stacks of absorbent pads, cartons of masks, nothing with good edges and almost nothing with obvious metal. Somebody had learned fast in here too.
Ren hit the door shut and dropped the internal latch.
Mina leaned in just long enough to look through the little window. Her face didn't move. She just stepped away from the glass.
"Good call."
Isaac breathed once through his teeth. "Yeah."
That was all he had.
Jadah looked at him like she wanted to ask what the hell that was and didn't trust the timing. Her shoulder was shaking now in small, angry tremors. The blanket around her hands had slipped, exposing one wrist. The shelving beside her gave a faint plastic rattle even though there was no air moving.
From the hall came a bright, cheerful knock.
Not on their door.
On the busted stairwell doorframe.
The young voice again.
"Ow."
Silence answered him.
Then the low voice from the landing man, farther back and colder.
"You talk too much."
A wet crash followed. Not enough context to enjoy.
Jadah flinched anyway.
Mina was already moving through the room, checking the rear wall, the ceiling line, the secondary panel at the back. No window. One vent. One old service hatch low near the floor with a plastic grille screwed over it.
There.
She crouched.
"Maintenance chase," she said. "Too small for comfort. Big enough for survival."
Ren crossed to it. "Locked."
Mina looked up at Jadah.
Jadah closed her eyes once. "Don't."
"I was going to ask if you could move the screws."
"That's worse."
"It's faster."
Ren took one knee by the hatch and held it steady. "Can you."
Jadah stared at the grille like it had insulted her lineage.
"I don't know."
"Then find out now," Mina said.
The young voice in the hall laughed again, closer to their door this time.
"You people are so good at making little boxes."
Something heavy struck the corridor wall outside. Not their wall. Adjacent. A bank of lockers maybe. The whole room shivered.
Jadah's breathing went high.
Isaac stepped in front of her before the panic could choose its own shape.
"Look at the hatch."
"That is literally the problem."
"I know. Look anyway."
She looked at him instead.
Good.
Better.
He pointed down without breaking eye contact. "Not the whole thing. One screw."
Mina and Ren both went quiet at that.
No pressure from them. No commands. Just room enough for the try.
Jadah licked once at her dry lip, then looked at the nearest plastic-coated screw in the hatch grille.
Nothing.
The voice outside the door hummed to itself.
"Found you."
The hallway light under the door dimmed.
Not out.
Blocked.
Someone standing there.
Jadah's jaw locked. A bead of sweat rolled from her hairline down the side of her face and caught under the cut at her jaw.
The screw twitched.
Once.
Then again.
Jadah made a tiny, furious sound in the back of her throat and held her hand very still at her side like even moving her fingers would spook it.
The screw turned a quarter inch.
Ren was on it immediately, fingertips catching the edge and twisting it the rest of the way free.
"Again."
"No one asked you to sound excited," Jadah snapped.
"Again," Ren repeated, not excited at all.
Outside, the low voice said, much nearer now, "He's behind the wall."
The young voice answered, amused. "Then pull him through."
The room did not like that sentence.
Neither did Isaac's chest. The thread jerked toward the far wall and then the floor and then nowhere useful at all. Too many directions now. Too much. He hated how empty his hands felt when they weren't holding anything that could matter.
Jadah got the second screw.
Then the third stuck.
The first real miss of panic hit her face.
Not dramatic. Just the split second where she thought of the door, the voices, the wall, Ty, the waiting room, all of it at once.
The stack of plastic-wrapped tubing on the shelf to her left slid six inches off-center and dropped.
The noise made her flinch harder.
The screw stopped moving.
Isaac caught her eyes before the room could.
"Not the shelf."
"Really."
"Jadah."
Her breathing shook.
He lowered his own voice until it was almost nothing. Just for her.
"You break the wrong thing and then what."
That landed.
Her mouth tightened. The anger came back in and pushed the fear a half step to the side. Good. Better than calm. More familiar.
She looked back at the screw.
It turned.
Ren ripped it free.
Mina pulled the grille off with both hands.
A black maintenance space opened behind it, ugly and narrow and smelling like dust, stale insulation, and old coolant.
From the hall came a bang against their door.
Not enough to break it. Enough to bow the plastic frame.
The young voice sighed.
"See? He never shares."
Mina pointed to the hatch. "Ren, case. Isaac, then her. I cover."
"No," Isaac said.
Three people looked at him.
He pointed at Jadah. "She goes before me."
Jadah blinked. "That's stupid."
"If something happens in there, I can shove you farther. You can't do that for me."
"That is a terrible sales pitch."
"Move."
That got the smallest, most exhausted corner of a smile out of her before it died.
Good enough.
Ren shoved the case through first, then flattened herself and fed it ahead of her one-handed into the dark crawlspace.
Mina took position by the door, gun up, body angled. "Fast."
Jadah got on her knees and stared into the black opening.
Her blanket-wrapped hands trembled.
"I hate this," she whispered.
"Nobody's selling tickets," Mina said.
Another bang hit the door.
A crack split through the upper panel.
Not a hand. Not a face. Just pressure finding weak points.
Isaac put one hand between Jadah's shoulder blades, careful of the bandage.
"Go."
She went.
Awkward. Angry. Breathing hard. But she went, dragging the blanket through after her like part of the room was trying to keep her.
Ren's voice came muffled from inside the shaft. "I've got her. Isaac."
He dropped to the floor and shoved into the hatch feet last, twisting around the bad shoulder and biting back the sound it wanted out of him. The shaft was tighter than Mina had made it sound. Of course it was. Dust stuck to his cheek. His ribs hated everything. Ahead of him Jadah was muttering a steady stream of profanity under her breath as she crawled, which was maybe the only comforting sound left in the hospital.
Behind him, Mina backed toward the hatch.
The door finally gave.
Not all at once.
The latch popped. The plastic frame shrieked. Something pressed through the opening too slowly, like it enjoyed the geometry of doors failing.
Mina fired twice.
The gunshots in the tight room were monstrous. Isaac's ears rang instantly.
A young man's voice laughed through it.
"Told you."
Then the lower, colder voice said, "Enough."
A body hit the floor.
Hard.
The room shook.
Mina dropped into the hatch after them and yanked the grille halfway back into place behind her by sheer spite, buying one second of cover that probably meant nothing and mattered anyway.
Then all four of them were in the dark.
The shaft bent left after six feet and widened just enough for a person to crawl without scraping skin off both shoulders at once. Ren had the lead. Jadah after her. Isaac behind Jadah. Mina last, gun somewhere awkward in the narrow dark and still somehow under control.
No light now except the weak green emergency strips bleeding through vent slats every ten feet.
The hospital sounded different from inside the walls.
Bigger.
Hollower.
Like every scream had to travel through bone.
Ahead, Ren said, "Intersection."
Mina answered from behind Isaac. "Right. Then down."
"How do you know."
"Because this hospital hates me personally."
Jadah almost laughed. It came out strangled and tired.
The shaft widened into a vertical drop with a ladder bolted to the side, old composite rungs instead of metal. Below, another run of maintenance passage disappeared into dark.
Ren went first, handing the case down before herself.
Jadah leaned over the edge, took one look, and closed her eyes. "Of course."
"You've already done worse ladders tonight," Isaac said.
"That does not make this one polite."
He got a hand on her arm. "Go."
She went.
The door they'd left behind somewhere above slammed open with a flat echo through the ducts.
Then footsteps.
Not running.
Measured.
Two different rhythms.
The young voice came thin and delighted through the shafting.
"There they are."
The other voice did not answer.
That was somehow worse.
Jadah was halfway down the ladder when her sock slipped on one rung slick with old dust. Isaac caught the back of her blanket wrap before she could peel off into the dark and drove all the pain in his shoulder into a single white line.
She froze.
Breathed once.
"Still got you," he said through his teeth.
She didn't look up.
Just nodded once and kept climbing.
By the time Isaac got down, Ren already had the case moving again through the lower maintenance run. Mina landed after him, one breath harder than the others and no complaint in it because apparently she'd decided complaint was for people who expected to live comfortably.
They turned right.
The shaft opened ten feet later into a service crawl above a suspended ceiling grid.
Voices below.
Real ones.
Hospital ones.
Panicked and human.
"—don't move the ventilator—"
"Where's the portable—"
"Jesus Christ, get pressure there—"
Mina stopped them with one hand.
Listened.
Then said, "ICU stepdown."
Ren looked down through the crack between tiles. "Too many people."
Mina nodded. "Keep going."
From behind them, somewhere back in the dark they'd just crossed, something touched the ladder rung above with a neat little tap.
Then another.
Then a voice, warm with admiration.
"He does make people run pretty."
Jadah shut her eyes.
Isaac felt the thread under his sternum go rigid and bright as wire.
Not behind now.
Ahead.
Straight ahead.
Something else waiting.
He looked past Ren into the dark service run in front of them.
"Stop."
No one argued this time.
Good.
Too tired for pride.
"What," Mina asked.
He pointed into the dark.
"Not there either."
The silence that followed was ugly because all of them understood exactly what that meant.
Not back.
Not forward.
Trapped in the walls of a hospital while things that used human voices learned their routes from both directions.
Below them, in the ICU stepdown unit, a baby started crying.
Above them, the vent line carried back a soft, patient laugh.
And in the black service run ahead, something metal gave a single answering click like the dark itself had just smiled.