The Doctor followed. He had to let the Master have control over this. There wasn't much the Doctor could do, apart from pretending to be the Valeayrd. A bit difficult to do, considering he was a bit drunk and holding onto the Valeyard's nearly-empty scotch bottle like it was a stolen prized possession.

"You might be able to get him to do silly things for you in exchange for affection," the Doctor said quietly, by ways of continuing their previous conversation. "Or not, knowing him, but it might be really brilliant if it worked."