Well, barbiedollwarhol, I think that he definitely has shown signs of interest--you lucky girl you.
Seriously, though: it probably is better to ignore his advances until the end of the semester, when he won't be as apt to get fired and you won't be as apt to be coined "
that girl who sleeps with her professors."
Believe me, regardless of whether you sleep with him or not: if you decide to date him while you're his student, you will be coined "that girl" by the other professors in the department as well as your fellow peers. Such a stigma is hard to recover from.
Anyway, good luck. I really hope he didn't do what I think he did in that bathroom...