If Waver won't fight his nature, Yin won't fight hers full of curiosity and wonder under all of that absence of emotion. She's not supposed to fight in the first place, so that's just her nature to be more passive about what she shouldn't feel anyway.

Yin listens intently, committing all of Waver's words to memory.

"That is useful information," she tells him, voice empty despite her gratitude. At least she knows of it ever happens to her, people will only have to deal with her inverse copy for a week. In her favor, is the fact she doesn't eat for flavor anyway, but just to survive. Nutrients to keep her functioning are the most important aspect, so she can handle that.