Sherlock (2010) S2 E2
Luvlinguae 2 points 6 months ago. (Contains Spoilers)

Major plot hole in this episode:
They never clearly explained if it was an aerosolized gas that was causing hallucinations or not. If it was, how it was delivered? How did it get in the lab? How did it get into the home of the young man? They only vaguely and quickly surmised that it was released via pressure plates at the hollow, but nothing more.