The Black Island: Part 1 - S1-E10
Other mistake: Mueller tries to shoot Tintin from outside the medicine room. He ends up shooting a bottle of chloroform. After it has been shot, the "C" on the bottle's label disappears from shot. (00:16:10)
The Black Island: Part 1 - S1-E10
Other mistake: Tintin runs upstairs and Mueller tries to shoot Tintin. He misses Tintin and shoots the door frame and the wall. When he shoots the wall, the bullet in the door frame tilts an inch. (00:16:00)
Chosen answer: It is a pill that makes alcohol taste disgusting.