The Doctor was still figuring out how he had ended up in this particular alternate universe. Actually, he had only just finished figuring out that he was in an alternate universe at all. He had been wandering down Bloomsbury Way, unable to put his finger on what made this London seem a little different from his London when he had passed a television store and was startled by the sound of his own voice coming from a display set. Slack-jawed, he paused to watch himself caper across the plasma screen until River Song's merry warning of "spoilers," seemingly directed less at the Doctor in the telly and more at the incredulous one with his nose pressed to the glass of the store front, shook him out his trance. He stepped back, nearly fell off the curb, and shot off down the street just in time for a disappointed television salesman with an armful of pamphlets to sigh and plod resignedly back to his desk.
The Doctor set the TARDIS to run a set of diagnostics and self-repair the tiny hull breach that must have somehow landed him here in the first place, and decided that in the meantime he needed to get his mind off of the unsettling fact that his life was a BBC show here. He was contemplating seeing a play in the West End or something when he passed a poster for an art exhibition that evening. Somehow drawn to it, he followed the signs to a bright little gallery with its front doors thrown invitingly open. He had been strolling through it for a few minutes, just appreciating the breadth of human imagination when a painting on a small pane of glass caught his eye. For the second time that day, the Doctor was astonished. His mind ran wild in the tiny, tiny split second between recognizing the script and processing what it said. How can this be? Are there Time Lords here? Has the war not occurred in this universe? Why hadn't I thought of that before? Then the words in front of him sunk in. He cocked his head to one side, then the other. He blinked. He snorted. And then he started laughing. He laughed until he was wheezing and tears were streaming down his face, and the other visitors were giving sideways glances to the young man in the bowtie who seemed to be having a total mental breakdown over an abstract circular design.
As he staggered out of the gallery, still howling with slightly hysterical laughter, he dropped a handful of coins (some of which may not have been from England or, indeed, Earth) into a donation jar and reflected on the wonderful absurdity of the situation. He was a telly show here. Of course there were no Time Lords, just the human race and its endless penchant for creativity and humor. He knew he might be stuck here for a while, but somehow that silly little glass painting had made him feel just a little bit better about the whole thing.