The Calculus Affair: Part 1 - S1-E12
Other mistake: When the taxi gets hit, the number plate reads "GE 7051" on the back of the car, but when the taxi falls into the water, the number plate reads "GE 7054" on the front of the car. The number plate should be the same on both ends. (00:14:55)
The Calculus Affair: Part 1 - S1-E12
Other mistake: One of the villains says "With pleasure" after looking at Calculus and his radio. The other villain has a cigarette in his mouth. In this shot, you can see the cigarette has two ends to it. The edge of it cannot be ash because that would have been washed away in the rain. (00:03:15)
The Calculus Affair: Part 1 - S1-E12
Other mistake: The villains look at Calculus on his radio. In this shot, Calculus has a reflection in the mirror but his eyes don't seem to have a reflection at all. (00:03:05)
Chosen answer: It is a pill that makes alcohol taste disgusting.