Other mistake: The Doctor says: "He's taking the suspended-animation chamber to the church." The subtitles say "[...] to the judge." (00:15:30)
Other mistake: Clara says "The dark, the sword, the forsaken, the temple." The subtitles say "The Doc [...]." (00:22:10)
Other mistake: The Fisher King says "The Time Lord... Lied." The subtitles say "The Time Lord... Night." (00:35:00)
Other mistake: The line spoken is "You mash up Vikings to make warrior juice." The subtitles say "You must have [...]." (00:12:30)
Revealing mistake: In several episodes of season 9, starting at "Under the Lake" and continuing through "Before the Flood", "The Girl Who Died" and "Sleep No More", the same white hallway model is used. For the first two episodes, this makes sense, since they play in the same location. However, the same hallway is used in "The Girl Who Died", when the men from Ashildr's village get blasted to death, and again in several scenes in "Sleep No More" when the characters run through the hallways. Also, it seems the control room from the underwater research center, where the characters hide from the ghosts in "Under the Lake" and "Before the Flood", is reused as the white room in "Hell Bent" when the Doctor pulls Clara out of her timeline, though in "Hell Bent" the room is nearly empty and the room in "Under the Lake" and "Before the Flood" is full of equipment.
The Husbands of River Song - S9-E14
Revealing mistake: When Hydroflax's head is sitting on the section of the TARDIS console with the telepathic circuits, the console is obviously sagging inward, as if made of rubber.
Factual error: By halfway through the episode, the plot is alternating between following Clara and Jac in London, the Doctor in the fictional Central Asian country of "Turmezistan", and Kate in New Mexico. Despite the three locations being scattered all around the world, only in London is it depicted to be nighttime at any point in the episode. Central Asia and the southwestern USA are both shown to be daytime, despite the two locations being over halfway around the world from each other, and the events all taking place at roughly the same time.
Continuity mistake: Davros' chair has metal parts which go over his shoulders - they are attached to the chair, not Davros. When the Doctor steals Davros' chair they disappear, but when Davros is back in it they have reappeared.
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