Laura has only spent a few months in London, and already she's learned some of the more interesting things about it's underground community. And she'd encountered a few characters amongst them, as well as within the humans around them.

Besides, she was from New York.

So really, she doesn't blink twice when the Doctor came barreling up to her asking if she recognized his face. "No, I'm afraid I don't- are you alright, sir?"