Ah, this one. They've had a handful of run-ins across her timeline, though never any outright altercations. She's no Time Lord, but she's far more useful (and reasonable) than most humans and has earned his semi-respect. Still, that she can never remember her own name amuses him to no end. He finds himself smirking back at her as he approaches, figuring she must have some hand in all this or else she's as trapped as he is.

"There's never been anything wrong with my memory, little girl." It's an almost friendly jab, to get her back for the whole Saxon thing. He's so over it.