The Black Island: Part 2 - S1-E11
Revealing mistake: Thomson and Thompson commandeer a plane. When the plane exits the screen in the shot where one of them says "Go up, go up", there are some sort of grey smudge marks on the screen that shouldn't be there. (00:31:25)
The Black Island: Part 2 - S1-E11
Revealing mistake: The mechanic the detectives presume to be a pilot says "This is my first flight". Thomson and Thompson turn their heads to each other whilst the mechanic speaks. Note how they have a black color in their eyes, but when they finish turning their heads, the color in the eyes of the detective on the left disappears for three frames, which reappears as soon as they turn their heads to the ground. (00:31:40)
Chosen answer: It is a pill that makes alcohol taste disgusting.