The Doctor didn't really like doing things in halves.
So, he promised Jack a proper Christmas, so he plugged the keyword "Christmas" into the randomizer and set the TARDIS to land wherever she deemed would be appropriate. He thought they'd land somewhere on Earth, maybe a classic Victorian Christmas, or one of the neon-light Christmases of 4333. That would be nice.
As she flew, he opened up one of the compartments on the console and quietly tucked away the cufflinks Jack had given him. Sentimental, he'd said before. Sentimental, but they were a gift. For all the Doctor knew, with the Marquis chasing them they might be the last thing he ever got from Jack.
He hoped not.
Ding. The console fell quietly and the Doctor raced over to the monitor.
Not even Earth. Odd.
"Christmas Eve," he said, grinning despite it all. "12136 AD. Not a bad year for Christmases, I think."