[Well, she does have a mean suplex, but none of this makes sense. Luckily (or unfortunately) she has experience dealing with mental instability. That doesn't mean she's good at it, of course, but maybe she can just play along for now. Would that make him feel better?]

Leon... [She frowns, shifting a bit closer to her tablet.] Leon, it's all right. I just didn't recognize your voice at first. [It's a blatant lie, but he's crying, and she doesn't know what else to do. Who the hell is Ansem, anyway?] You're safe, it's okay, you're just... Seeing things. It's a trick.

[Tifa has no clue if she's actually helping or if this is making everything so much worse. But if she'd been hallucinating and someone like Cloud didn't recognize her, she thinks she would be that much more frightened.]