The Doktor stares at him. They have moved into another of the rooms on the zeppelin, which the Major can but usually chooses not to monitor, particularly when he's thinking about war, so he's the only one who can really be appealed to. Zorrin is simply smoking a cigarette and ignoring the proceedings.
"Listen. I'm going to have to remove your eyes and replace the retinas without unattatching them. I'm going to have to cause your muscles to deteriorate and then regrow them from scratch. I'm going to have to add additional nerves to your system and the biological equivalent of surge protectors to your brain. And to do all that, I'm going to have to remove roughly half your flesh and nearly all of your skin. So tell me, do you really want to be conscious and able to feel pain when I do all that?"