The Doctor wasn't exhilarated, exactly. Mostly he was aching and burning. He wouldn't have been surprised if he'd literally had smoke pouring out of his ears. Even the work he'd done with Yana had been agonizing. This was ripping him apart. It just didn't matter. Hell, he barely even noticed, once he'd gotten his metaphorical back into it, and he was more than willing to let the Master's glee carry him. He'd been giving everything he had. Somewhere, feeling that shift and the Master's happiness, he found more. Teeth gritted, eyes closed tight, hand gripping the Master's neck a little harder, he shoved. Brutally hard, damaging and determined and unrelenting and unyeilding.