The Master didn't know how to deal with this sense of vertigo - to know that he once would have chosen to do something differently, but to realize he didn't really want to do it that way, right this minute.
What would happen if he decided he wanted to? It would be easy...the only person really standing in his way was the Doctor, but the Doctor trusted him, which meant...
He broke off that train of thought, feeling a little sick to his stomach.
"I'm not him, Captain. I could have been, but I'm not. Did the Doctor stop him? I'm sure he did."