I watched the Torchwood episode "Fragments" again this evening with friends, and loved it as much as before. As tends to happen after viewing this episode - and it was the first time for for some people - we started discussing the role of UNIT. I totted out my theory that either Martha would see the violations of human rights that UNIT was perpetuating, and stop it, or that the Doctor had set Martha up by getting her the job in UNIT and was expecting her to act.
I'd love to know what the favours were that he did for UNIT, that they owe him favours for in return.