Xion's face definitely falls. That's... about the same reaction she'd gotten last time. He doesn't remember being in the Tower before, and he doesn't remember her, which means he's also from after she returned to Sora. Or maybe before she even existed.

She looks down and away. Somehow this is so much harder than it'd been last time.

"I... yeah... sort of," she says, quietly, "Or... you did. It's... hard to explain."