He smiles. "No, you don't."

The Doctor doesn't realize what he's doing at first. His hands are on his head and he thinks maybe he's trying to lower him to the ground, maybe he's about to let him die there. Then, he realizes the feeling. The trance, the healing trance he's very pointedly not used until this point.

"No! Don't you dare!"

But the Master is stronger than him psychically and he's physically weakened. He can't stop it.