He shone it at the top of the steel door, where the thick metal was already glowing a dull, angry red.

“They’re using a thermal lance,” Nathan said.

His voice was flat, stripped of all emotion by sheer panic.

“The heat will buckle the deadbolts in ten minutes, not thirty,” he said.

“Can we block it?” I asked.

“No,” he said, shining the light around the small, concrete-walled room.

The flashlight beam settled on the metal ventilation intake grate near the ceiling.

“I have to go up,” Nathan said, his face pale under the white light.

He walked over to the heavy metal shelves holding our emergency supplies.

“Nathan, no,” I said. “The duct is too narrow.”

“The primary bypass is right behind that intake,” he said.

He began pulling heavy plastic crates off the shelves, stacking them to make a platform.

“If I can cut the backup line from there, the magnetic seals will lock down completely,” he explained.

“They won’t be able to melt through the secondary alloy without blowing the whole frame.”

“But you’ll be trapped in the ceiling,” I said.