"But they don't yet know how to build a time machine?"
"No. They don't."
"Do you?"
Again, Garwood's reflex was to lie. "I think so," he admitted instead. "I'm pretty close, anyway."
They walked on in silence for a few more paces. "I'm sure you realize," Davidson said at last, "the implications of what you're saying."
Garwood sighed. "Do try to remember, Major, that I was worrying about all this long before you were even on the scene."
"Perhaps. But my experience with scientists has been that you often have a tendency toward tunnel vision, so it never hurts to check. Have you told anyone yet? Or left any hard copies of the technique?"
"No, to both."
"Well, that's a start." Davidson threw him a sideways look. "Unfortunately, it won't hold anyone for long. If I'm smart enough to figure out what the increase in the Garwood Effect implies, Saunders is certainly smart enough to do the same."
Garwood looked over at Davidson's face, and the knot in his stomach tightened further as he remembered what the other had once said about Saunders using hypnosis against him. "Then I have to get away again before that happens," he said in a quiet voice.
Davidson shook his head. "That won't be easy to do a second time."
"Then I'll need help, won't I?"
Davidson didn't reply for several seconds. "Perhaps," he said at last. "But bear in mind that above everything else I have my duty to consider."
"I understand," Garwood nodded.
Davidson eyed him. "Do you, Doctor? Do you really?"
Garwood met his eyes... and at long last, he really did understand.
Davidson wasn't offering him safe passage to that mythical wilderness Garwood had so often longed for. He was offering only to help Garwood keep the secret of time travel out of Saunders's grasp. To keep it away from a world that such a secret would surely destroy.
Offering the only way out that was guaranteed to be permanent.
Garwood's heart was thudding in his ears, and he could feel sweat gathering on his upper lip. "And when," he heard himself say, "would your duty require you to take that action?"
"When it was clear there was no longer any choice," Davidson said evenly. "When you finally proved safe time travel was impossible, for instance. Or perhaps when you showed a working time machine could be built."
They'd reached the door to Garwood's office now. "But if I instead proved that the probability-shift effect would in fact keep a working time machine from actually being built?" Garwood asked, turning to face the other. "What then?"
"Then it's not a working time machine, is it?" Davidson countered.
Garwood took a deep breath. "Major... I want a working time machine built even less than you do. Believe me."
"I hope so," Davidson nodded, his eyes steady on Garwood's. "Because you and I may be the only ones here who feel that way... and speaking for myself, I know only one way to keep your equations from bringing chaos onto the world. I hope I don't have to use it."
A violent shiver ran up Garwood's back. "I do, too," he managed. Turning the doorknob with a shaking hand, he fled from Davidson's eyes to the safety of his office.
To the relative safety, anyway, of his office.
For several minutes he paced the room, his pounding heart only gradually calming down. A long time ago, before his break from Backdrop, he'd contemplated suicide as the only sure way to escape the cloud of destruction around him. But it had never been a serious consideration, and he'd turned instead to his escape-and-research plan.
A plan which had eventually ended in failure. And now, with the stakes even higher than they'd been back then, death was once again being presented to him as the only sure way to keep the genie in the bottle.
Only this time the decision wasn't necessarily going to be his. And to add irony to the whole thing, Davidson's presence here was ultimately his own fault. If he hadn't skipped out of Backdrop six months ago, the major would never even have come onto the scene.
Or maybe he would have. With the contorted circular logic that seemed to drive the probability-shift effect nothing could be taken for granted. Besides, if Davidson hadn't caught him, perhaps someone less intelligent would have. Someone who might have brushed aside his fears and forced him onto that airplane at Chanute AFB. If that had happened—if the effect had then precipitated a crash—
He shook his head to clear it. It was, he thought bitterly, like the old college bull sessions about free will versus predestination. There were no answers, ever; and you could go around in circles all night chasing after them. On one hand, the probability-shift effect could destroy engines; on the other, as Davidson himself had pointed out, it logically shouldn't be able to crash a plane that Garwood himself was on...
Garwood frowned, train of thought breaking as a wisp of something brushed past his mind. Davidson... airplane...?
And with a sudden flood of adrenaline, the answer came to him.
Maybe.
Deep in thought, he barely noticed the knock at the door. "Who is it?" he called mechanically.
"Saunders," the other's familiar voice came through the panel.
Garwood licked his lips, shifting his mind as best he could back to the real world. The next few minutes could be crucial ones indeed.... "Come in," he called.
"I got a message that you wanted to see me," Saunders said, glancing toward the terminal as he came into the room. "More equipment trouble?"
"Always," Garwood nodded, waving him to a chair. "But that's not why I called you here. I think I may have some good news."
Saunders's eyes probed Garwood's face as he sank into the proffered seat. "Oh? What kind?"
Garwood hesitated. "It'll depend, of course, on just what kind of latitude you're willing to allow me—how much control I'll have on this—and I'll tell you up front that if you buck me you'll wind up with nothing. Understand?"
"It would be hard not to," Saunders said dryly, "considering that you've been making these same demands since you got here. What am I promising not to interfere with this time?"
Garwood took a deep breath. "I'm ready," he said, "to build you a time machine."
VI
Within a few days the Garwood Effect damage that had been occurring sporadically throughout Backdrop's several fabrication areas jumped nearly eight hundred percent. A few days after that, repair and replacement equipment began to be shipped into the complex at a correspondingly increased rate, almost—but not quite—masking the even more dramatic flood of non-damage-control shipping also entering Backdrop. The invoice lists for the latter made for interesting reading: esoteric electronic and mechanical equipment, exotic metals, specialized machine tools for both macro and micro work, odd power supplies—it ran the entire gamut.
And for Davidson, the invoices combined with the damage reports were all the proof he needed.
Garwood had figured out how to build his time machine. And was building it.
Damn him. Hissing between his teeth, Davidson leaned wearily back into his chair and blanked the last of the invoices from his terminal screen. So Garwood had been lying through his teeth all along. Lying about his fears concerning time travel; lying about his disagreements with Dr. Saunders; lying about how noble and self-sacrificing he was willing to be to keep the world safe from the wildfire Garwood Effect a time machine would create.
And Davidson, that supposedly expert reader of people, had fallen for the whole act like a novice investigator.
Firmly, he shook the thought away. Bruised pride was far and away the least of his considerations at the moment. If Garwood was building a time machine...
But could he in fact build it?
Davidson gnawed at the inside of his cheek, listening to the logic spin in circles in his head. Garwood had suggested more than once that the Garwood Effect would destroy a time machine piecemeal before it could even be assembled. Had he been lying about that, too? It had seemed reasonable enough at the time... but then why would he and Saunders even bother trying? No, there had to be something else happening, something Garwood had managed to leave out of his argument and which Davidson hadn't caught on his own.