The Doctor chooses to ignore her attitude, which is the real, mature way of being unimpressed. "Oh I don't know, I'd say it's more a beige-y taupe," he offers, with mildly disgusted humour. It's what she gets, for her sour disposition. "I'm afraid I don't have any idea." He doesn't sound particularly sorry to tell her this. In another incarnation, he might have sounded quite gleeful. Even in this one, it's quite intriguing. "Strange architecture, can't say I recognise it. Very likely not human." She looks human, but that doesn't mean very much, and she had been threatening to eat mysterious street vermin.

He doesn't comment that the place looks like an aging war zone; she doesn't want obvious information, remember. And it is quite obvious. Whatever happened here was likely very unpleasant, to leave a city in such a state. "I wonder if there's anyone left to tell us anything at all. Seems like the inhabitants may have evacuated." Or worse. "Who are you? And what are you going to name your new friend?"