Jack is not scholarly-minded by nature, but sometimes a little theoretical work is unavoidable, especially for those who use a great deal of cyphers and code and have nasty, suspicious and above all twisty minds (like Jack). His notebook is slowly being filled with number combinations, together with bits and pieces of Thirbite algebra.

(So much easier than the earth variety, provided you have the necessary languages to translate back when you're done.)

Since, however, there's only so much dry data you can take when you are by nature a social creature, he's doing this at a table in the middle of the bar, with the vague hope that someone will interrupt.

He can't be rude enough to ignore anyone, and then he'll have a legitimate excuse to wrap things up for the day.

Jack has spent the last couple of weeks in a strange balance between relaxing and becoming increasingly stressed. The Doctor is conspicuously absent, and it seems almost certain that if he wants to get back to his home universe - Cardiff or otherwise - he needs to go out to the same place he came in from.

That wasn't fun last time.

So instead of going over options in his head again, he's sitting in his new room drafting a hugely belated resignation letter to Lilly - she's another one he can't find.