There is a limit to how long a person can survive in a below-freezing environment. Does she normally store her clothes at such a cold temperature. Could this be connected to her temperament during the first part of the movie. That was unkind. Of course, since they're not in an atmosphere, they wear breath masks.
Space is a vacuum, and so is the interior of any asteroid cave.
Similarly, the gravity seems pretty strong for an asteroid of that size. In my older video version, you can see Luke's head reappear after he jumps down to the trampoline, following Vader. In the THX version, the last couple seconds are cut. They're chased for a while. They try to jump to hyperspace, but fail.