Well, this is an entirely different pale-haired woman from the one he met on the previous island. He doesn't know if the pointed ears mean anything; certainly if he's insisting his own appearance doesn't mark him as inhuman, then hers doesn't either, necessarily. It's hard to say in this place. Could human strength pry open that door? Forcing them isn't something he's thought to try, yet. It was always a futile effort when he was young.

The polite thing to do would be to offer assistance, or at least to leave her to her business and move on, but with this place already wearing on him, Sephiroth doesn't give a damn about manners. He's content to stand back and watch. Which may be somewhat creepy given the faint glow in his eyes and the giant sword he's carrying. He doesn't mean it to be, but clearly he's not trying to be friendly either.