The Doctor never crosses his own timeline. It's one of his rules, right up there with "The Doctor lies." And so how it is that he somehow ends up arriving outside of Magpie's Televisions on the day of Elizabeth II's coronation is certainly not his own doing. Or at least that's what he tells himself.
Despite his better judgment (a rather normal occurrence) he traces the path from years ago that he somehow still remembers. The streets are quiet. Everyone is inside with their brand new televisions waiting for the broadcast. Ignorant of what they will be saved from. And who will do the saving.
He stops on the sidewalk opposite the row of pretty brick townhouses. He knows which one it is. He sees movement behind the curtains, and a moment later the door opens.
And out she steps.
In her pink dress, her hair done up in the style of the times, she may just be the most wonderful thing he's seen in a long, long time.
For just a second, her eyes dart around the quiet street, before something catches her attention: a young man across the street in a tweed jacket and red bow tie, watching her. Something about him is so very familiar to her. But before she can figure it out, her attention is called back to her own situation.
The Doctor continues to watch as the younger version of himself emerges from the townhouse door. He knows every detail of that man, knows that that man may recognize him. He ducks silently behind a tree, but continues to peer around the trunk at her. Allowing himself just a few moments of painful longing.
Before the pair from the past (his past, that is) continue on their way, she glances back at where he had been standing a moment before. Her expression turns perplexed as she gazes at the spot of empty sidewalk. The younger Doctor pulls her back from her reverie.
He allows himself just one more luxury.
"Rose."
He barely hears the whisper himself. But for a split second, she seems to hesitate. Then again, maybe the light is just playing tricks with his eyes.
Soon she the pair turns the corner, and the Doctor is once again alone.
He has to run back to his TARDIS before he tears a hole in the space-time continuum.
But that's what he gets for crossing his own timeline.