He felt as if he were crawling against a breeze, and that confused him for longer than it should have. Of course there would be a breeze. Air didn’t just sit because it was underground. It still moved.
His thought process seemed clogged, mud in the gears, and he tried to blame whatever drug lingered in his system, but the more frightening possibility had nothing to do with that. Mental difficulties went hand in hand with physical difficulties in hypothermia. Simple thinking became complex.
He searched for a word that should have been easy to find, the one that explained what that cold cave air was doing to him, a word he’d written in one of those notebooks. He had crawled for quite a while before he came up with the word: convection. You lost heat via convection when air circulated. You lost heat via conduction when you came in contact with cold surfaces. You lost heat via radiation when you didn’t have sufficient clothing; you lost heat via evaporation when you sweat; and you lost heat via respiration when you breathed. Those were all the ways you could find yourself in a hypothermic state. Any one of them could kill you, and Mark was experiencing every one of them.
Stop thinking about all the ways it’s bad. Just concentrate on going forward. On doing the one thing you can do to help yourself. There’s nothing left of you now but the essential. The only resources you have are your mind and body. Don’t waste them.
It was hard to follow his own commands. Whatever confidence and concentration he might have been able to muster in other circumstances was drained by the darkness. It was one thing to summon the hope of salvation when you were crawling down a mountain or swimming away from a sinking ship; it was another to call it up when you were trying to escape blackness by moving into more blackness.
There’s a reason they bury people underground, he thought. It’s the place where they come to an end. And you’re there now.
So was Lauren. He thought of her casket being lowered into the earth, put into the blackness and sealed away. He was down there with her now. And with Sarah Martin. How sad it was that they’d put her back underground when her last moments had surely involved a desperate hope to return to the surface. In the end, they’d just sent her remains down to the very world she’d died trying to escape. How terrible.
Maybe not; maybe she was cremated and her ashes scattered somewhere high. You don’t know. She could be aboveground. You should find out, if you ever have a chance.
Strange thoughts, dark thoughts. Everything here was dark, though. There was no choice about that. He thought maybe his hands weren’t working as well as they had been earlier. Opening and closing a little slower.
Hands are just tired. That’s all.
Everything was coming at him in a swirl; a thought would be there and then something would spiral in and replace it and later the original thought would shoot back. He tried to do some simple math, addition and subtraction. Exercise the brain, keep it focused. No, wait, exercising it might be bad. Hadn’t he read somewhere that mental willpower drained glucose faster than physical exertion? That didn’t seem possible, but he thought it was what he’d read. They’d done a test, something involving weight lifting and problem solving. He was almost sure of it. So what should he think about? What took the least amount of will?
Quitting.
Sure. But it was cold on the stone, and he was warmer moving. When moving stopped being appealing or when he could no longer feel a difference, that was when he would know...
He stopped crawling and cocked his head. Something had changed. There were more sounds here.
He tried to quiet his breathing — it was more panting than breathing — and get a bearing on where the sound was coming from. No longer did he fear snakes. Any sound seemed friendly. It meant there was something else down here in the dark, meant that he wasn’t entirely alone. By now, this was only a good thing.
To the right.
Dripping and splashing. There was moving water somewhere ahead. And at some point, it had come from the surface.
He found the source in another twenty feet, a shallow creek, just a few inches deep, but enough. He cupped his palms and lifted the water to his lips and drank greedily. It was muddy and tasted of the earth, and fine bits of grit coated his tongue and his teeth, but it was also delicious.
He drank enough to slake the thirst and then forced himself to stop, not wanting to push it and not sure if he’d even be able to hold it down. For a brief time he felt nauseated, but that passed and he moved along the underground stream just far enough to determine that it was going uphill.
The only thing he could possibly do to make himself colder, to accelerate his course toward hypothermia and death, would be to slip into water. His core temperature would begin to plummet then, and he had no means of raising it.
He just wasn’t sure that he had any other choice. Staying dry was the thing to do if you believed that rescue might be on the way. Mark did not. So far as he knew, he’d been left in this place to die. Getting out was up to him. And while getting wet would hasten the onset of hypothermia, he knew he didn’t have much time on that front anyhow. The difficulty in concentrating and the loss of his fine motor skills had already arrived, but what concerned Mark more was not the symptoms he was noticing but the one he’d stopped noticing: shivering. At first blush, this might seem like a good thing, an adaptation to the temperature. That was a cruel prank of biology, though. The body never really adapted to a change in temperature. His body was reacting to the temperature, but reacting was very different than adapting. While shivering was an unpleasant sensation, it generated heat.
He attempted to check his pulse, but he had trouble feeling the beats because of numb fingertips. As he ran his hands over his body, trying to warm himself, he was aware of how muscular he felt. His chest and abdominal muscles and triceps were taut the way they might be after a good weight-lifting session. This was the worst sign yet. An increase in muscle tone meant he was well down the road to hypothermia. In severe cases, the muscles actually began to mimic rigor mortis, the body dying around you even while you still drew breath.
“Got to stay moving,” he said, and his speech was slurred. Getting wet and getting colder might speed things along, but he didn’t have enough time left to worry about wasting it.
He crawled into the stream going against the current. There wasn’t much force to it here, but the water sounded louder ahead, and that might be a problem.
He had nothing but problems, though. Might as well add another. He put his head down and crawled, and time and distance faded from him, and for a long while there was nothing but the cold. He splashed on, and the pitch of the slope became much steeper, turning his crawl into a climb. It took an enormous effort — several times he fell and slid back down, banging painfully against the rocks — but he wasn’t certain how much distance he’d gained for all the work.