This scene mystifies me as well.
I didn't think she was staring at the sword, specifically... alright, she had it at her throat, and it might have reminded her of New Moon considering it's curved etc., but the clue *I* picked up on wasn't the sword but the "Just get off... ...of..." that precedes her "ohhh..."-ing.
I thought she was putting herself in Cutter's shoes there, with Kahvi coercing him into something. A bit silly, I guess. She wasn't planning to rape him, after all. But at the time that's exactly what I thought. Hm.