Viv gave a soft sound of distress.
Bertra ignored her. “As for Dr. Liu? That was an accident. Can you believe it? She helped make the concoction, and she sprayed herself. Dumbass.”
They reached the end of the hall. A metal door stood half-open—supplies stacked along the shelves. Cleaning fluid. Paper rolls. Sealed boxes.
Vexler jerked the gun toward the closet. “Inside. Now.”
Viv went in first. Abigail followed. Kohnex stepped in without a word, followed by Laurel. The room smelled like bleach and old dust. Everything inside was quiet.
Vexler stepped back, grinning faintly. “I’ll be back,” he said. “Or rather, the spray will.” He slammed the door. The lock turned with a loud rattle.
Laurel cataloged the entire room in a second. “Tim? I need your jacket.”
He shrugged out of it and handed it over. She ducked down and shoved it between the door and floor.
“You think that will work?” Abigail asked.
“Can’t hurt.” Laurel turned to study the supply shelf. Nothing too dangerous there.
Viv sank to the floor to sit, and Kohnex followed suit, looking dazed again.
Laurel grabbed three bottles off the shelf—one labeledDESCALER,anotherPEROXIDE CLEANER,and the third markedAMMONIA-BASED DEGREASER.It was all cheap and generic industrial stock.
She set them down. “We mix the peroxide and descaler first. That’ll give us heat, gas expansion, and the exothermic reaction we need. Then we’ll add ammonia for vapor pressure.”
“We need pressureanddirection,” Abigail said, stepping in close.
Laurel nodded. “We’re going to make a directional blast. Controlled. Somewhat.” She reached for a mop bucket that was lightweight plastic, warped slightly from age, and tore off the handle. Then she grabbed a roll of foil and a box of steel wool pads. She shredded the foil and packed it into the base with the wool, pouring in a shallow layer of descaler. The chemical stench bit immediately into the air.
Viv coughed once and covered her nose with her sleeve.
“Aluminum and acid. Unstable gas production,” Laurel explained, working fast. “It’ll heat and build. When we add the peroxide, the whole thing kicks.”
Kohnex stared. “How do you know this stuff ?”
“I read.” Laurel didn’t look up. “Now give me that bottle.”
He handed her the peroxide. She poured half of it over the mixture. It hissed, immediately bubbling. Foam climbed over the aluminum, slow at first, then racing.
“Ammonia is last,” Abigail said.
Laurel had to hurry. “Seal it up.”
They slammed the lid on the bucket and duct-taped it shut with a roll from the shelf. Laurel tilted it sideways, pressed the taped spout directly against the bottom edge of the door, and lined it up with the lock assembly.
“Everybody go to the back far corner and cover your ears,” Laurel said quietly.
They obeyed.
Laurel twisted the spray cap off the ammonia and dumped it through a small cut she’d made in the lid with a rusted paint scraper. She sealed the hole with pressure from her palm, counted to five, then scrambled back.
The bucket swelled with its plastic creaking and deforming.
Then it blew.
Chapter 37
The bucket detonated with a wet, concussive crack.It wasn’t quite an explosion, not quite a chemical rupture, but something messier and louder than it should have been in a space that small. The air recoiled. The door shuddered violently in its frame, its metal at the base flaring outward in a warped curl. Smoke hissed out in thick gray ribbons, sharp and acidic.
