"Stop it." The Doctor warned, "I'm not arguing with you; we're not going to wake up Mina or upset Donna. I'm in no state to fight you." The Doctor was trying to diffuse the situation. It didn't take a brain surgeon to know that the Master would barely have to even push the Doctor and he'd topple over. He was far too weak both physically and mentally.

He knew the Master was broken, and knew even better being in his own crazed state just how he was poorly coping. The Doctor barely was capable of it himself. "Now calm down."