Silly me! She wasn’t a soldier, or a pilot; she’s a scientist!
It’s so obvious, now.
She is the head scientist of a fourty-strong team who have landed on a remote planet to study the alien structures there. Their landing craft mysteriously malfunctioned just before touchdown, causing it to crash land, and now they have to wait several of the planets days before their mother ship, on AI pilot, can come back within telemetry range, as she has headed into a nearby nebula to get some readings from a strange star.
That was two days ago. Since then, five of the scientist’s team have vanished.
The structures they are investigating are a vast labyrinth of uncertain purpose. Though the atmosphere outside is very cold, and does not contain enough oxygen for humans to breath for more than a few minutes, inside, the atmosphere is perfect for humans. The temperature in the buildings is warm, and there is a constant breeze, though no one has yet figured out how it is generated, of even where it comes from.
In the time that the five scientists have vanished, the team’s two military-grade cyborgs have fought several pitched battles with seemingly non-existent foes, foes who register on none of the teams devices. The cyborgs have slowly been taking damage, and need to be repaired by the ships AI very soon, or they will not be able to defend the team much longer.
The scientist has a lot on her plate.
After a thousand years of struggle, the sweet, good demon managed to break through to our plane of reality, hoping for a better life.