She got to a point where she simply could not run anymore, so she permitted herself to drop into a brisk walk while she drank more water—she hadn’t been drinking enough, the CamelBak was only half empty—and ate another couple of bars. She was now on something that almost felt like a proper hike through the woods. Still gaining altitude but no longer with the sense of clinging to a cliff face. Gazing ahead and up-slope through increasingly common gaps between trees, she saw the high terrain that she had both longed for and dreaded all through the ascent, and towering above it the bare scarp of Abandon Mountain, which had nothing to recommend it as a tourist attraction unless you were a big fan of bleak. It looked like a science-fiction magazine cover, a mountain on some dead moon of Jupiter.
It was during this little respite that she heard the sound of a helicopter somewhere and debated whether she ought to run out into the open and flag it down. But it was hopeless; the chopper was a good distance away and the sight lines obscured by trees.
If only she had saved some of those bright pastel garments so that she could wave them in the air.
Speaking of which, the air was now bitingly cold on her shoulders. She bolted the last of her energy bar and forced herself to accelerate into a trot, then slowly build that up into a run.
She was just hitting her stride when she heard a sharp cracking boom. Because of the way it echoed around all the neighboring slopes, she found it difficult to judge direction. She was fairly certain, though, that it had sounded out of the direction from which she had just come. Miles away.
There was no one moment, no one place when she made the decision to go for it. The trees became thinner and thinner, the sight lines became clearer and longer, the ground angled more and more steeply under her feet. Minutes ago, she had been running across nearly level ground. But now she noticed that she was scrambling, almost on all fours, up a talus slope; looking back and down to judge her progress, she saw a good quarter of a mile of perfectly open ground behind and below her, terminated in the distance by a fringe of scrubby undergrowth that shortly developed into proper forest.
Down in that forest she could see movement. At least one man, possibly two of them. They were at most five minutes behind her: a sufficient head start to keep her alive in the dense forest down below, but, up here, just enough to make it a challenging shot.
She snapped her head back around to scan the slope above her, hoping she might see a place to take cover.
In most ways, this place could not have been worse. During her geoengineering studies, she had learned all about the angle of repose, which was the slope that a heap of particulate matter naturally adopted over time; it explained the shape of an anthill, a mound of sugar, a pile of gravel, or a mountain of scree. The angle was different for each type of material. Its exact value was not important here. What was important was that the angle was everywhere the same, and so slopes made of such materials tended to be ruler straight. There were no mounds or bulges to hide behind.
And—as she kept being reminded—they were inherently unstable. As long as she remained on areas of larger rocks, her weight was not sufficient to break anything loose, but when she strayed into sandy or gravely areas she set off little avalanches. Nothing big enough to be dangerous, either to her or (unfortunately) those below her, but enough to give her the impression that she was climbing on a treadmill, burning energy but, like Sisyphus, going nowhere.