It goes to Eleven. (Jack Harkness)
He also knew that Pond was in the City. He knew that there was a madman around who cared very little about the psychological trauma he inflicted upon people, nor did he seem to care much about who got hurt during his 'lessons.' He knew that he needed to seek out a 'Dean Winchester' for details.
The Doctor also knew that, no matter how much it pained him to stay in one spot, he couldn't leave. Not while this 'Trickster' was loose in the City. Not until he knew what made the City tick and how to ensure the safety of its residents. In a way, the wild goose chase that the Trickster had sent him upon had come to the desired conclusion, even if the Doctor now counted its perpetrator among his enemies.
So, reluctantly, after his 'guest' in the TARDIS had seen himself out, the Doctor set the coordinates not for places elsewhere in time and space but for a sidewalk in the heart of the City. He wanted to find Pond before she could get herself into too much trouble, and he'd have a better chance of picking her up on the sensors if he were in a central location. The TARDIS dematerialized from its spot outside the Magic Box and, with a tell-tale vrwooosh-vrwoosh, re-emerged in what was (at the moment) a spot near the geographical heart of the City. For now, that spot was just down from a cheese shop (aptly titled 'The Big Cheese') and across the street from an English style pub. It was interesting; usually the instruments were precise about the 'when' and 'where' of the TARDIS's physical location, but apparently being in the City made details scarce. He wasn't surprised. Of course the City would interfere in his ability to pinpoint things. He suspected that he wouldn't be able to trace the changing streets as they moved about, either.
The Doctor set the TARDIS to start taking readings then made his way to the doors. He needed to find a telephone book and see if he couldn't get a number for this 'Winchester' fellow.
The man who stepped out of the blue Police Call Box was not anyone Jack Harkness was likely to recognize. For one, he had the baby-face of a man still in his mid-twenties, and the previous Doctor's long coat and pinstripes were gone. Still, who else would take the time to lock the TARDIS and give her a fond pat on her side, the way you might part from an old friend?
((OOC: This is the last of my spam for today. I swear.))