To be fair, though, Kazuki's first thought was pretty much what Sensei would have preferred, she just didn't realize she could ask her to wait (or that Sensei even would?) and due to this didn't think it would work.
Well, that was something... Really not a happy story, at least not yet. Reluctantly agreeing to go out because you don't want to lose a friend. The little excited heartbeat at the very end of the last extra page does give some hope for the future, though, since she's clearly starting to fall now as well.