if they decide to imprison the Master in the TARDIS properly, shoudl we do a load of little timeskips to show them trying to persuade him over time?
Say every few weeks? I imagine it woudl take a good few months before the Master relents and tells them how to bring him back.
(plus it gives lizzie a chance to grow up a little more

)
ooh! maybe it's when it's coming up to lizzie's first birthday that John and the Doctor decide enough is enough and desperately try to force the master to tell them, since they don't want jack to miss her birthday.
hmm