Somehow I thought that this episode was kinda rushed. Even tho the whole series wasn't "bad", for some reason I felt that even on all episodes until now there were gaps.
As someone else said, it didn't really felt that Sana and Nanaka really loved each other, other than supporting, there were never really kisses or even hugs (well, there was one in episode 12-13, but that one doesn't really count IMO).