The Doctor looked a little surprised, maybe even a little hurt, at Jack's demand - for a second. Then the expression dropped off with a shrug. He was curious, and anyway, there was no way he was going to force Jack to stay on Arcadia. But if he wanted to play it that way, fine.

He fished the sonic out of his jacket and passed it over, placing the handle in Jack's palm with a look of slightly exaggerated exasperation. Then he leaned back and gave Jack another, more appraising look. "You've definitely come up in the universe," he noted. "Fancy new title. Fancy green girlfriend." Or whatever Jack wanted to call her.