Startling, Aziraphale backed up slightly. "Oh, my apologies," he said automatically, before he realized that it was disingenuous to apologize for something he didn't actually feel very sorry for. The Doctor was doing this in public, after all. Really he should be more worried about other sorts of surveillance.

"Oh . . . " He wiggled his fingers, trying to explain what was so intriguing. "The general gist. You seem very determined and - focused, where others are confused. It's impressive, really."