Travis stared at the thing. It was hard to imagine what else Paige could have meant.
“It would be easy to do,” he said. “Switch it off with the delay, and then carry the cylinder through the iris during the minute and a half it stays open.”
“You’d have to be out of your mind,” Bethany said. “What happens when the iris shuts behind you? Now you’re stuck seventy years in the future, with a machine that can only take you seventy years further into the future. You’d never get home.”
“What if it doesn’t work like that? What if turning it on in the future just opens the iris back to the present time? Like a toggle. Back and forth.”
“How would it know to do that?” Bethany said. “How would it know it was in the future?”
“I don’t know. Maybe it’s something simple. Maybe it senses when it’s taken through the iris, and switches itself into reverse. We’ll never know how it works, but think of what we just heard. Paige said you can take it through and come back. She knew a lot more about this thing than we do.”
He watched Bethany mull it over. Watched her warm to it.
“The logic adds up,” she said. “Someone built this thing for a purpose. I can’t see the use of something that just leapfrogs you further and further ahead in time, and never lets you come back. Forward and back makes more sense.”
“It also explains why the cylinders came as a pair,” Travis said. “Think about it. Who knows what this kind of machine was meant for, but we can imagine any number of things. It could be some military scouting tool. Use it to survey the aftermath of a war you haven’t even fought yet. Hell, it could be farm equipment. Say there’s some high-value crop that takes seven decades to mature. Sow the seeds, step through the iris and reap the rewards right away. But whatever the use, its makers had a reason to allow the delayed shutoff. That way you can take the cylinder with you when you go through the iris. Not hard to imagine why they’d want to. Leaving it behind, switched on, is a major vulnerability. Look at the precautions we had to take, setting it up so nothing could get at it from the other side. But here’s the thing: taking it with you would be risky too. Extremely risky, in fact. Picture yourself putting this thing to casual use. Like it’s a socket wrench or a screwdriver. You’re using it all day long, going back and forth between two points in time, hauling food supplies or weapons or whatever. Can you think of the mistake you might make? It would be the easiest thing to do, and if you did it you’d be in a world of trouble.”
Bethany’s eyes narrowed. She thought about it. “You could accidentally leave the cylinder behind. Leave it on the other side of the iris when it closed.”
Travis nodded. “It would happen one of two ways. Either you leave it in the future, in which case there’s no way to retrieve it except to sit on your ass and wait several decades, or else you leave it in the past and trap yourself in the future, in which case you’re absolutely screwed.”
Bethany walked over to the armchair. Stared down at the cylinder.
“You’d want a backup copy,” she said.
“You’d need a backup copy. Like a skydiver needs a reserve chute. Because some mistakes you can’t afford to make even once. You’d have a duplicate cylinder, and you’d strap it to your back and never take it off, at least not while you were using the first one.”
Bethany met his eyes. “It makes sense that Paige and the others would’ve figured this out. In the desert they had both cylinders. They could have tested this idea without any risk of getting stranded. Just leave one of them switched on, and use the other one to find out whether or not the iris brings you back to the present time.”
Travis nodded. It all added up.
A silence drew out.
“We could be wrong about this,” Bethany said.
“We could be very wrong.”
“Just plain old wrong would be bad enough. If we try this and it doesn’t work, we’re stuck over there.”
“If we try it and it does work,” Travis said, “then we can take the cylinder into the future, carry it up to the ninth floor of that ruin on M Street, and step back into the present time right inside the room where they’re holding Paige.”
The idea seemed to wash over Bethany like a breeze on a spring day.
“Nice,” she said.
Chapter Seventeen
They repositioned the cylinder so that it projected the iris to a different part of the hotel room—closer to the building’s interior, and away from the part that’d collapsed in the future. They found a spot that would allow them to step through onto a solid girder in the ruins. There was a sturdy oak limb hanging over it, which would offer easy transit to the ground.
Travis stepped through onto the beam. Bethany stood in the room, next to the cylinder. She put her finger over the third button and looked at him.
“Say when,” she said.