It had the potential to be an OK episode, the story about the scientist and the missing medicine, but it just got silly, to quote Graham Chapman in Monty Python.
The episode is in my bottom 3 of least favourites tieing with Bad Apple and Night Out
I don't get the dislike of Bad Apple. It's far more believable than say, Loving Arms (where was this factory that Fred Booth made the guns at and how did Arty Ward find him? The scenes with his wife are pretty lame) and Visiting Fireman which has been discussed lately. The Bigger They Are & Golden Boy are other episodes I think are not as good as Bad Apple. Max Deller is just not believable, certainly wouldn't scare me.