That's not how plane crashes work. 

...It's also not accomplishing anything to sit here in the wet silty mud, getting wet and muddy, and mentally yelling at Reality that the situation she's apparently perceiving is physically impossible and doesn't make any sense. 

"Tsi-imbi," Merrin says to the quiet empty air, almost absentmindedly.

It's a strange kind of quiet. She can hear water moving, a quiet whispering from nearby and a louder rushing off in the distance, and that's the only sound. ...When she concentrates, she might also be able to hear a distant sighing that could be wind. She concentrates even harder, and can pick out very soft...clicking or popping noises? Coming from the sand around her, at irregular intervals. 

That's it. No other sound at all. 

...The tide seems to be on its way out, and the irregular popping-crackling might be the sound of the newly-exposed tidal flats literally freezing, because it's shockingly cold. Enough that Merrin's brain seems to be trying to reject it as some kind of bizarre sensory illusion, because it doesn't fit with anything else in her surroundings. The - ocean? - is apparently liquid. 

She stands up, to avoid getting any wetter, and looks around. 

Her Exception Handling wilderness survival and emergency medicine kit boxes are haphazardly scattered around her, some on rocks, some with their corners sunk into the wet silt. It's almost as though some capricious giant randomly dropped her, and them, out of the sky. 

NOTHING ABOUT THIS SITUATION MAKES ANY SENSE. 

...Also, if she just stands here repeatedly rejecting all of her sensory input as impossible and not making sense, then - well, she has no idea really, because she doesn't even have a hypothesis yet for what's actually happening, but if she's actually in an environment with ambient temperatures of at least -30º C, which is what it feels like, then she will DIE of HYPOTHERMIA with her emergency survival supplies right there. 

Merrin is going to provisionally give up on forming any coherent hypotheses for where she is, or how or why she ended up here, and instead focus on locating and unpacking the box with her power armor in it as fast as she possibly can. It's amphibious, with a built-in air supply, and rated to handle -50º C air temperatures, though operating in conditions that cold will drain the battery pretty fast. 

It's designed to be quick to put on with help, and possible to get into solo, but doing it solo is not as fast as she might hope, especially when she's starting out in comfortable clothing suitable for long-range air travel and now somewhat covered in wet mud and she needs to strip out of that first while her hands are already in the process of rapidly losing dexterity. By the time she has the armor on, her brain has stopped disbelieving the "cold" sensory signals in favor of FREAKING OUT about them and shivering uncontrollably. 

But the suit heating is on, and she should warm up from here without needing further actions from her. 

Merrin turns around on the spot to get a proper look at her surroundings. 

That doesn't look like anywhere. 

Merrin sits down, after a few moments, and stares stupidly at the horizon, which does not resemble any geographical location she's ever heard of. Why is everything purple. Why does the sky look wrong.

Why is she here, alone, with her survival kit and no sign of anything or anyone else, and not True Dead???? 

It takes Merrin what is in hindsight a really embarrassingly long time to piece together several disparate observations into a theory. 

The observations:

- This does not look like anywhere in dath ilan 

- She could gather more data by climbing to the top of the ridge and yet she's not doing that. She's sitting here on the tidal flats, which are rapidly frosting over, because she's tired. 

- She's really, really, really confused and failing to find traction on any of the pieces of her confusion

- She...has...a headache...? 

....This isn't dath ilan.

Therefore, it's a different planet. 

Merrin is having trouble thinking or doing things and has weird symptoms.

...And she's sitting here breathing the air normally, having not actually sealed the helmet fully out of some unthinking "not really liking how it restricts her peripheral vision" motivation, and also something on the suit panel is beeping an alarm, but Merrin puts it together in the second before she actually looks to see what the alarm is. 

There's no reason to assume that an entirely different planet, even one with air that initially seems breathable, has air with the same oxygen content. And so, by Merrin looks down and sees that the alarm is 'low oxygen detected', this is no longer particularly a surprise and she just feels very silly. 

She seals the helmet and the suit takes care of things from there. 

A minute or so later, she has less of a headache and feels a LOT more capable of being vertical. 

Wow. Merrin was aware that hypoxia can be hard to notice internally, because it impairs the metacognition that you need to notice you have a problem in the first place, but she has TRAINING for this and yet it took LIKE FIVE MINUTES for her to diagnose the problem and she was in fact completely tuning out the alarm trying to alert her of the problem and all of that is really quite embarrassing. She'll have to bring it up in the - 

- debrief.

That almost certainly isn't going to happen.

Because this isn't a training simulation, this is...something else. 

Put together the information she has. 

Her last memory is of a plane crashing. Merrin's understanding of the world confidently predicted that she would, at that point, cease having any experiences. 

Instead she's - apparently experiencing the actually-quite-recognizable fiction trope of finding herself on an exoplanet with various intriguing and plot-generating environmental hazards? With her Exception Handling gear all inexplicably along with her, which...is at least hopefully hinting at the version of the trope where the main character can, with great ingenuity, use the resources she has to survive? 

Merrin kind of still wants to yell at Reality that this is incredibly silly and doesn't make sense and should therefore not be happening. 

However, just because Reality is apparently insane, doesn't mean that Merrin would be making particularly sane choices if she reacted to all of this by closing her eyes and saying "tsi-imbi" repeatedly until someone rescued her. 

This appears to be the situation that exists to be interacted with. And...if she just rolls with the premise, it is in fact true that Merrin is rather unusually prepared for the "survival on an exoplanet" story trope. The reason it keeps feeling like a training scenario that she's going to get to debrief afterward is because it's totally one that Exception Handling would throw at her, if it were possible. 

Though even if it were physically within the capabilities of Civilization to arrange this for a training scenario, which Merrin really doesn't think it is, she doesn't think that Exception Handling would arrange to have her experience it without warning like this. It feels out of character. There are scenarios they might throw at her by surprise, where she's not necessarily prepared has to improvise with non-optimized equipment, but not 'surprise: you're on another planet'. If Exception Handling had access to instantaneous-travel to other planets with different atmospheres, Merrin is pretty sure she would get at least a briefing beforehand and a list of the situations in which she could expect them to call off the scenario and rescue her.

So she should not be expecting to be rescued, if she gets herself into something she can't handle. 

Okay. Time to focus, and stop wasting mental cycles on disbelieving that any of this is really happening, and instead use her entire brain toward surviving it if it is. 

There's no particular reason to think that 'low oxygen atmosphere' and 'subzero temperatures' are the only life-threatening hazards. Merrin needs to orient, and form hypotheses about what sort of planet this is and what its properties are, and then test those hypotheses, and then make plans to survive both the immediate and the longer-term dangers. 

She accesses the wrist panel on her power armor to check what environmental parameters it's picking up. 

The basic suite is pretty straightforward. Ambient air temperature: -38.1º C. She was not wrong that it's really cold.

Ambient pressure: ...pretty normal. Slightly low for literal sea level, but not for, say, 1000m altitude, which would not give anyone altitude sicks. 

Atmospheric oxygen fraction, though: 13.5%. Eep. That's not quite low enough that she would have progressed to unconsciousness and seizures within minutes if the suit hadn't warned her, but...she's actually rather fortunate that it was so cold. If she'd arrived to a comfortable balmy temperature, she might have started exploring without first putting on the armor and switching it on for the heating, and she probably would have realized what was wrong before she collapsed, but...possibly not actually in time to fix it while already impaired. 

....Well, she's gotten as far as analyzing the hazards she already knows about and that's already enough to alert her to some very serious problems!

Namely: at these temperatures, her suit has maybe 18 hours of battery life. And less oxygen supply than that. And she's not predicting a rescue in the next 18 hours. 

Okay. What are her solutions. 

She has a field oxygen concentrator, in the extended medical kit. And one caniser of compressed oxygen, for use in conditions where for some reason she can't set up the oxygen concentrator. She can adapt the various components to refill her suit's tank from the canister, and then fill the canister from the oxygen concentrator, and that gives her mobility. If she doesn't need mobility, she can park herself next to the oxygen concentrator and pipe it directly into her suit; it produces slightly more than she'll need at rest, so she could even still accumulate some extra for storage. Or, given that she needs to figure out shelter anyway once the suit runs out of battery, she could just sit around with nasal cannula on her. The atmosphere isn't toxic, it just doesn't have quite enough oxygen for humans to stay healthy. 

The oxygen concentrator also needs power to run. 

She has batteries. At 15º C she could power it for a couple of days just off stored power. 

Merrin has no reason to think her situation will end in a rescue in two days. 

She has a portable kit with solar panels. The sky looks clear, so if she's lucky, and she can find a nice undisturbed place to set up camp, she can generate solar power to refill batteries during the day, use stored power at night, have some backup stored oxygen (as a backup for her backup, she does have three sodium chlorate candles which will generate 6h of oxygen each, but if she has to use them, they're gone.) 

...Great. Progress. She's broken it down to 'if she can find a place to camp, she can indefinitely keep breathing air with enough oxygen in it.' She also needs water, and food, but she has some of each with her - enough water for several days, enough food for a month - and she has a filter and purification tablets if she can find freshwater locally, and she doesn't have a pre-built kit to evaporate and distill seawater but she knows how they work and she has a lot of emergency medical equipment and supplies that she doesn't need and can instead repurpose for survival. ...She'll need a heat source, she can't evaporate enough water by the heat of the sun if it's winter - it has to be winter, if it were this cold all the time there wouldn't be liquid oceans -

- actually, no, she's confused.

It's -38º C. There should be icebergs. Not just frost on the ground and some delicate icing-over of the little river flowing down the center of its channel, surrounded on either side by hundreds of meters of silt and rocks. There should probably be snow??? A desert might be completely bare of snow even in the depths of winter, but deserts are usually in the continental interior, not coastal. She's standing right in the intertidal zone. There should be regular precipitation, here, and if it's this cold it should be coming down as snow, so where is the snow? 

...She checks the suit readout again. You know, just in case she hallucinated it the first time or something. 

Still -37.4º C. 

That's...about half a degree warmer, actually, which is maybe hopeful that the winter days are warmer than the winter nights. She arrived more or less right at dawn. She's been here for...twenty minutes? Huh, it feels like it must be less than that, or the sun would have covered more distance, it's still only a little ways above the horizon. 

Merrin navigates to see the temperature trend. 

It's definitely getting warmer! By about 0.6º C per ten minutes. Well, that's at least hopeful in terms of the peak afternoon temperature being less frigid. The coldest temperatures are usually going to be shortly before dawn, so if it warms up enough and takes long enough to cool fully overnight, then -40º C is probably the worst she has to deal with, and she might even be okay in just warm clothing for the warmest part of the afternoon. She'll absolutely need to figure out some kind of shelter by nightfall, that's still the next step, and by tomorrow she ideally needs a good place for solar panel setup...