Timeline

36:28:04

In the control room, an alarm rang insistently. The technicians both got up from their consoles and started out of the room. Stern felt Gordon grab him firmly by the arm.

"We have to go," Gordon said. "The air's contaminated from the hydrofluoric acid. The transit pad is toxic. And the fumes will be up here, too, soon enough." He began to lead Stern out of the control room.

Stern glanced back at the screen, at the jumble of girders in smoke in the transit site. "But what if they try to come back when everybody is gone?"

"Don't worry," Gordon said. "That can't happen. The wreckage will trigger the infrared. The sensors need six feet on all sides, remember? Two meters. They don't have it. So the sensors won't let the machines come back. Not until we get all that cleared away."

"How long will it take to clear it away?"

"First, we have to exchange the air in the cave."

Gordon took Stern back to the long corridor leading to the main elevator. There were a lot of people in the corridor, all leaving. Their voices echoed in the tunnel.

"Exchange the air in the cave?" Stern said. "That's a huge volume. How long will that take?"

Gordon said, "In theory, it takes nine hours."

"In theory?"

"We've never had to do it before," Gordon said. "But we have the capacity, of course. The big fans should cut in any minute."

A few seconds later, a roaring sound filled the tunnel. Stern felt a blast of wind press his body, tug at his clothes.

"And after they exchange all the air? What then?"

"We rebuild the transit pad and wait for them to come back," Gordon said. "Just the way we were planning to do."

"And if they try to come back before you're ready for them?"

"It's not a problem, David. The machine will just refuse. It'll pop them right back to where they were. For the time being."

"So they're stranded," Stern said.

"For the moment," Gordon said. "Yes. They're stranded. And there's nothing we can do about it."