And the Master does indeed look as if he's been slapped. Ohhhh, why does the Doctor push him. After he's given him such a gift, too. A few (relatively) pain-free moments-- a breather-- before the sort of end he deserves.

"Am I?" And he giggles, the sound short and sharp and just slightly out of breath. Giddy, even. The Master stands there, staring at the Doctor with that hideous grin-- the kind that comes not from any true amusement, but utter rage.

In the next second he's dropped to his knees, lunging toward the Doctor in some sort of frenzied attack.