The Pyramid at the End of the World - S10-E8
Visible crew/equipment: Right before the TARDIS materializes in the lab at Agrofuel, there's an overhead shot of Erica at the desk, and the two green tape X marks on the floor behind her are visible, precisely where Douglas had collapsed and his white protective gear should be. Note there's an earlier overhead shot of the same area before the incident, when Erica brings Douglas the coffee, and those tape marks are not there. (00:32:50)
Visible crew/equipment: When Bill and Nardole run away at the end of the countdown, the reflections of the camera dolly and camera operator are visible on the CERN countdown board. (00:35:55)
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 after everything the Master's put him through hurts him more deeply than death would.
Captain Defenestrator