There is a split second where the girl's appearance takes on anger. It's not the answer she wanted, but really any answer wasn't. She was so young! She wasn't supposed to die! But the man she'd been talking to (and for quite a while) had kept dodging her even if his face suggested he knew the answer. And if HE survived, why couldn't she?

But it's only a moment before that anger collapses in and she just looks sad. "Thank you. No one would answer me." She held onto the orange she's already been given, almost clutching onto it the way she may have held onto a favored toy when she was younger. "I should go."

Yes, Vader would have continued to ask her questions - but he'd told her she could leave when she wanted to. And she thought she wanted to, now.