To be fair, people can blush in any number of awkward situations. It doesn't mean that because you're embarrassed about being nude in front of someone, even if it's of the same sex, that you're gay.
Am I the only on that believes people can just be platonic in manga anymore or does everyone have to want to bone someone just because they blushed once?
That being said, I definitely think it would be interesting if Tokimaru had a crush on Ai and that is why he is so dedicated, but it'd be fine if he didn't.