[Mashita's expression is hard to read at first--he doesn't seem bothered that Yashiki has turned this back around to questioning his identity... in fact, that's a good thing really. Even if he's not an imposter, it's a good sign that Yashiki would think to do this if someone really had been running around pretending to be Mashita.

Though, about what had been said...]

"The living and the dead can't coexist. If you try to accept their feelings, you'll just end up getting pulled in."

[And then, he manages a smile, though it's a tad derisive.]

Judging from your tone, you still don't agree with that, do you?