I looked back the way we had come.

Another steel door was sliding down behind us.

They were trapping us in this corridor.

“Where is the manual override?” I asked.

“There isn’t one on this side,” Vance said. “The control room handles the locks.”

I looked at the walls, searching for an alternative exit.

I spotted a narrow metal door marked with a yellow high-voltage sign.

“Where does that lead?” I asked.

“The utility shafts,” Vance said. “It’s just pipes and wiring.”

“Open it,” I said.

He pulled a keycard from his pocket with trembling fingers.

He swiped it against the reader.

The light blinked green, and the lock clicked open.

I pushed him inside and pulled the door shut behind us.

A second later, the heavy blast door outside slammed shut.

The vibration rattled the metal walls around us.

We were in a narrow, dark space.

Huge insulated pipes ran along the walls, humming with pressure.

The floor was made of metal grating.

I could see a sheer drop into the darkness below.

“How do we reach sublevel two from here?” I asked.