The plot twist is obviously that there isn’t a lone one that likes him, they all do (Including probably sensei), it’s just that one of these messed up chicks is messed up enough to take it to that level
I'm guessing, it's not one of the four and is the one who says good morning to him? or like everyone else says: the sensei, but she doesn't actually like him and this is her ploy so he interacts with the other 4 more.
Nobody bothered by having a scar on your face and obviously bothered by it only to get threatened with a knife again is somehow cute, interesting, funny and mysterious?