That was a sound Jack knew all-too well. He had been out and about, walking through and exploring the town and taking readings as he wandered about. But, then, he'd heard it. The sound he'd spent years listening for, keeping his ear trained and waiting for the TARDIS to land on the Rift to refuel.
Which was why Jack suddenly found himself picking up his pace and running in the direction, his speed increasing as the call box came into sight. Jack didn't know which one he'd see (or, really, if it would be a regeneration that he'd know for that matter) but it didn't matter. The TARDIS meant the Doctor was here and, for Jack? This place couldn't get any better. He had Ianto -- he had Rose -- and now he had the Doctor. Who could ask for anything more?
Jack skidded to a stop, walking now rather than approaching at the break-neck speed. At last the Doctor came into view and Jack grinned when he saw who it was. And the perfect one to give a piece of his mind to for, as happy as Jack was to see the Doctor, part of him was still fairly pissed he'd been left behind with nothing but Dalek dust.
"Well, well, Doctor," Jack said, arms wrapped around his chest and grinned. "Look who dropped in."