Responses
I don't think she's a yandere but we'll see I guess. They've shown multiple times that she just doesn't like being around people. The MC is the budding exception since he has a cute dog, is seemingly a decent person, and is more skilled than most of the people she's seen so far.
I'm genuinely so happy that they have something besides the usual tsundere and they made the sniper into a yandere. It's been a long time since I've read something that had a yandere.