Daleks in Manhattan (1) - S3-E4
Plot hole: The guy working for the Daleks offers the homeless men in Hooverville a dollar a day to go into the sewer because the Daleks need more people. Most of the people refused and one called it slave wages. If they were not getting paid until they came back, and since the Daleks were planning on experimenting on them, the people weren't going to come back; why not offer them a large amount of money big enough to entice them but small enough not to be suspicious?
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