Despite the fact that I generally like this episode and its combination of noir and The Thing, it has its share of cringe moments.
I guess she was kind of a person of interest as opposed to an actual suspect, so she wasn't actually like under arrest, but the point was that her character is very rash and flees from problems or else reacts defensively. Which makes her reasoned refusal of LaForge's offer to "put in a good word for her" all the more baffling. Ahh, the writers would develop romantic relationships between characters and then suddenly and jarringly drop it. Right.