Continuity mistake: When Amy lies down on the tree stump, her hair is all over her face, but on the wide shot her hair is behind her head. (00:12:46)
Continuity mistake: After the Doctor finds out River's in Stormcage, when he pulls out of the pocket computer to look at the readings from the time crack, it rotates in his hand between shots. (00:19:24)
Continuity mistake: In the last scene, when Amy attempts to seduce the Doctor, she pulls his suspenders off his shoulders and he pulls them back on. As a result, the suspenders change position between shots.
Chosen answer: The Master knows that deep down, he deserves death for the crimes that he's committed throughout his life, and since he regards The Doctor as his arch-foe, he expects it to be at his hands. The fact that The Doctor is still willing to forgive him for all of his crimes hurts him more deeply than death would.
Captain Defenestrator