The Night of the Tottering Tontine - S2-E16
Continuity mistake: There's a coiled wire sticking out of the spine of the book that electrocutes Baring. It's there in close-up, but disappears in full-shot. (00:42:50)
The Night of the Tottering Tontine - S2-E16
Continuity mistake: West demonstrates how the knife popped out of the chair upholstery when pressure was applied. His hand is inches from the blade in one shot, then disappears in the next close-up view. When it cuts back to the master shot, his hand is once again beside the knife. (00:20:20)
The Night of the Tottering Tontine - S2-E16
Deliberate mistake: The knife that has just killed one of the investors doesn't have a trace of blood on it. No one had time to clean it off. (00:20:00)
The Night of the Tottering Tontine - S2-E16
Plot hole: They said they couldn't leave the room because the door wouldn't open and then they all went to their rooms. How did they get out?