"I was good once. Then I met you," the Master mused, a fond look on his face because hey, it had a grain of truth to it. Though it was vastly more complicated and a lot more his fault than he made it sound. "I can be good again. If you put me in a room with my hands uncuffed, I'll behave. I mean you can't watch me twenty four hours a day, you'll get bored and I'll get bored. So let's just leave me to it, hmm?"

Let him roam free in his room to slowly but surely find his own way out and completely trash the TARDIS in the process. "Oh dear, you have tripped yourself up here, haven't you? I mean what else can you do but lock me in a room? Tying me up all day would be cruel and I assume free roam is dangerous. So what's it to be, Doctor?"