Pretty much as expected. It's unfortunate on Miku's part, and I don't really think Ema is being a responsible adult here, but I guess you could say it's hard to argue with chemistry. Anna wasn't really good for Miku, but well Miku also pushed for a relationship when Anna wasn't interested.
Unlike some comments, I don't think everyone in this comic is an asshole, I think they're just immature, and a bit aggressive in their immaturity (Yoshino is an exception, definitely an asshole).