Zed tried not to think about the trip back to the surface. The one that would have had him cutting it close on oxygen reserves, even if he hadn’t been delayed. The one that he would now have to make on a busted leg, assuming he could somehow get it unpinned from the boulder that was doing its very best to keep him right where he was.

  Work the problem.

  Work it with what?

  Zed looked at what he had. There really wasn’t much to see. He had the sample case, and that was pretty much it. He hadn’t brought any tools, which, in hindsight, would have been a good idea even without knowing he was going to get stuck. Something to keep in mind next time he struck off on his own to an alien cave in the middle of the night.

  Zed laughed out loud. He wasn’t sure why he was laughing, but he also didn’t know what else to do. Was he really just going to die here and turn into that skeleton in a spacesuit that gets found by the hero in science fiction horror stories?

  At least they were smart enough to bring along a companion to help get them out of a jam, even if it was just some robot sidekick, Zed thought. Actually, that's not entirely true.

  He didn’t have a robot, but he did have a companion in the cartoonish Douglas, and his leg assist exoskeleton did technically make him part robot at the moment. Maybe there was a way to make those two things work to his advantage right now.

  “Douglas, can you control my exoskeleton if it’s no longer attached to my suit?” Zed asked.

  Douglas appeared, this time with a torso and limbs, which he used to gesture at the jointed metal plates that ran alongside Zed's legs. Highlights appeared around the battery pack. Douglas gave a thumbs up.

  “OK, show me how to detach one of these without disconnecting the power,” Zed said, his words rushed as a plan began to take shape in his mind.

  He needed to get out of here as fast as possible, assuming this worked and didn’t just crush his leg entirely to paste.

  Under Douglas’s watchful eye and with his painfully specific directions, Zed removed the exoskeleton from his right leg. He was only going to have one shot at this. The left exoskeleton was pinned under the rock along with his leg. It would have been helpful to have both of them to work with, but try as he might, it wouldn’t budge.

  With the right exo detached, Zed reached down to where the rock was pinning his leg. He needed to place the knee joint of the exo under the boulder and as close to his ankle as he could manage. At the moment, it was still in a zig-zag shape. There was no way to fit it into the tiny gap as it was.

  “Douglas, straighten the right exo leg.”

  A chime of acknowledgment sounded, and the robotic leg straightened into something resembling a mechanical yardstick with a power supply at one end.

  Zed slid it under the boulder as far as he could. He felt it hit the back of the space.

  Crap.

  It wasn’t quite as deep as the knee joint, but he would just have to hope it was close enough to get the leverage he needed. Zed wasn’t sure how this was going to go, but he had a feeling he was only going to get one shot at it. Either it would work and he’d be free, or he was about to make things even worse for himself.

  Zed took a deep breath.

  “Alright, Douglas, compress the detached exo leg. Slowly.”

  Another chime sounded, and the straightened leg started to bend. Zed pressed down hard on the top of it until he felt enough pressure build to keep it firmly wedged against the floor and the boulder. Zed couldn’t hear anything outside of his suit, but he could feel the exo’s motors vibrating as they struggled to lift the boulder’s considerable weight.

  To Zed’s surprise, the boulder shuddered. Then, with glacial speed, it started to rise. The pressure on his leg began to ease, millimeter by millimeter. A few more seconds, and he’d be free.

  For a glorious moment, Zed thought that this was going to be it. He’d actually worked the problem and found a solution! Then panic returned as the boulder shifted, pivoting over the struggling exoskeleton and coming down on his ankle from a new angle.

  This was a different pain—a new pain that sent a wave of nausea shuddering through Zed’s exhausted body. Whatever hope he’d maintained that he might get free with nothing more than a sprain vanished as he felt a sickening crunch.

  It was several minutes before shock numbed the pain enough for Zed to take in his new situation. To his surprise, the exoskeleton leg hadn’t actually failed. Unfortunately, that hadn’t stopped the rock from shifting into a new and even worse position.

  “Douglas,” Zed said through gritted teeth, “what’s the status of the right exo leg?”

  Douglas gave Zed a thumbs down and stuck out his tongue.

  Zed sometimes wondered if it had been a mistake to give Douglas a library of cartoon pantomime options instead of just giving him a voice. This was definitely one of those times.

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  Looks like I’m truly stuck between a rock and a hard place, Zed thought, and then burst into manic laughter until tears rolled down his cheeks.

  He might have cackled like that for hours if he hadn’t twisted his leg slightly. The fresh wave of pain brought him back to his all-too-humorless reality.

  Something was different, though. When he moved, the left exoskeleton leg had moved with him. He looked at the place where the rock had previously pinned it. The rock was no longer resting on it.

  “Douglas, I’m gonna need another walkthrough to get this left exo leg off. Go through it at double speed this time, OK?”

  Once he'd finished getting the left exoskeleton detached and jammed it firmly under the other side of his trapped leg, Zed once more found himself hoping for the best while every muscle tensed in anticipation of the horrific worst.

  At this point, it couldn’t really get much worse, and there was a certain relief in that. When your baseline is withering in a spacesuit while enduring the pain of a crushed ankle, any change is a positive one.

  “Douglas, compress left exo leg. Do it as slowly as you can.”

  Zed felt his left ankle burn as if stabbed by a thousand glowing-hot pokers. For a moment, he assumed something had gone wrong, but then the pain eased somewhat. He looked down to find the boulder slowly but surely lifting off his leg. Zed put both hands on the ground and carefully slid himself backward.

  The material of his suit caught for a moment on the rising boulder. It shifted and looked like it might slide off the exo and come crashing down on Zed again. To his great relief, the exo held.

  With as much care as he could manage, Zed slid his leg the last few centimeters back. He was careful not to look at his ankle too closely for fear that he would find it bent at some unnatural angle that would make him want to puke in his helmet even more than he already did.

  And then, just like that, he was free. Now Zed did look at his ankle, if only to confirm that it wasn’t just wishful thinking.

  Seeing that his leg was indeed free, Zed moved with a speed that was ill-advised and scooted back away from the rock that had caused him so much pain. A few moments later, something shifted in the passage, and both exoskeleton legs were crushed under a fresh run of boulders.

  Zed winced, imagining what it would have felt like if his leg had still been where it had been a few seconds earlier.

  With a groan that turned into more of a whimper as he moved, Zed looked around and took stock of his new situation.

  With one problem solved, he suddenly found himself facing several more, and they were no less daunting than the last. He was going to have to find a way to hobble out of here on this broken ankle, and fast.

  “Douglas, is there anything the suit can do about a broken leg? Any pain meds or something?”

  Douglas appeared beside Zed with what seemed to be a half-amused, half-chastising look. He displayed more text from the turtle suit user manual.

  "...your suit is, however, capable of providing a makeshift splint. At your command, it can apply firm, even pressure to the broken limb to prevent further damage from occurring."

  “OK, that’s something at least. Will it make it hurt less?”

  Douglas stared at him with a blank grin. He shook his head.

  “Ya know, Douglas, in situations like this, you do come across as a bit of a sociopath. I’m gonna have to work on your bedside manner, even if it is a cartoon version.”

  Zed looked down at his leg. With the pressure of the rocks removed, he could feel his heartbeat pounding in his ankle.

  “Alright, do it. Splint me, or whatever you call it.”

  Starting from the interior of his left boot and shooting up to the middle of Zed’s calf, the suit constricted with terrifying speed. The pain was intense, but the worst of it was mercifully brief.

  The ache was still there, but as Zed sat up, he could tell it had at least helped stabilize whatever was broken. Now he just needed some kind of staff or cane to help him get up.

  “There’s just such a sad lack of usable branches on Mars,” Zed mumbled to himself.

  Douglas appeared again, this time in his full form, standing between Zed’s outstretched legs and nearly causing him to fall back in surprise.

  Douglas placed his blue gloves on the hips of his spacesuit and struck a heroic pose.

  Douglas gestured with his hands to either side of Zed’s legs, where the damaged but intact exoskeleton legs lay. The boulder had forced them into their straightened state. He bent down as if to pick one up. As his hand passed through the real-life version, he picked up a virtual representation of the legs. With a twist, he removed the battery pack and rotated the joint at the foot end. Douglas made a flourish, flipping it over and holding the virtual exo leg out to Zed. Except it didn't look like a leg anymore but a strangely serviceable cane. Douglas gave a playful bow and vanished once more.

  Zed felt a little ashamed that he hadn’t thought of it himself. It seemed kind of obvious now. He did as Douglas had suggested and detached the battery pack from the end of each leg. He was left with what looked like two long, flat metal canes.

  He decided to use only one since he would need to carry the sample case in the other hand. Zed put his weight on each and chose the one that seemed the sturdiest.

  He stooped with the slow care of the freshly injured and picked up the sample case. It seemed to have made it through the whole affair unscathed.

  “Here we go,” Zed said and hobbled forward, looking as old and broken as he felt.

  There were very few times in Zed’s life when he truly felt like he’d pushed himself beyond his comfortable physical limits. The physical aspects of astronaut training had been difficult, at least for him, but nothing like the gauntlet the astronauts of the previous century had endured.

  In truth, Zed had never imagined it was possible to be so utterly exhausted—not just physically, but mentally. As he dragged himself down the stone passages, the pain in his ankle grew with every cautious step. But he didn’t have time to be cautious. With the oxygen he had left, he should have been sprinting for dear life, but he couldn’t.

  That was when Zed confronted another first. He’d never faced a moment in his life where the very real possibility of death loomed before him. With each passing minute, Zed was finding it harder and harder to see any other possible ending. He just couldn’t move fast enough.

  The idea of inevitable death didn’t feel like he thought it would. He realized that while he had known he would die someday, and understood that death could come at any moment, he had never truly believed it. This brought everything into stark focus. There was a clarity that imminent death brought in its wake. Zed wished he could have experienced this insight without the need for death.

  If I had believed in death, maybe I’d have lived a little more, Zed thought as tendrils of fatigue and pain continued to engulf his mind.

  Then the darkness came for Zed. He attempted to take another step, but his makeshift cane caught on a rock, causing him to drop his full weight onto his injured leg. Whatever Zed thought his pain tolerance might be, he found himself flying past it into oblivion.

  Zed watched as the hard, rocky floor came up to meet him. It approached in slow motion, as if he were falling through water. Before he could feel the impact, a merciful blanket of unconsciousness wrapped itself around his mind.

  In that moment, he had one last thought.

  I really am the skeleton astronaut that gets found in a cave.