Well, at least the cringy, creepy parts didn't last that long. That Ingrid's top just had to be torn off first right before the baddie gets killed is some pretty blatant fanservice timing though. He could've gotten a cool entrance even without it.
Yeah, but there might have been a more opportunistic moment for him to land the blow depending. Makoto is an assassin; we should assume that he waited until the best opportunity where the evil priest's guard was down before making that move.
However, I'm willing to bet he isn't dead; just because he looks human doesn't mean he will die like one.