From where I see it, I think that that Mihashi-girl didn't really notice or acknowledge that she was in love with Emi. Instead she wanted Emi to make a move on her. She probably wanted to be saved by her and got into those two relationships. And Emi was probably really disappointed by that behavior and walked away, because she didn't want to date her out of pity. Partly I find that amazing on the other hand it really is cold. But that's just how Emi is I guess. Kinda like her character though.
Amazing oneshot. How much is said in so few pages. How horrible things can go, when people don't talk...