"With our lives!" the Doctor agreed, thinking of how many times that Master had come through for him. He rubbed his face, studying Jack, who was looking horribly pale and drawn still. "Romana's right, though, Jack. I don't think we should do anything more now. You need to get some rest. With any luck, the drug will start to wear off soon and you can start to rebuild your shields - and the TARDIS will protect you till then."
Jack wanted desperately to protest, but he knew he wasn't in any condition for, well, anything. The sooner he rested, the sooner he could go and punch the living daylights out of the Master.