It is not credible that the hypnotic gas would work as depicted. It comes in through the ventilators, so it would not freeze everyone in place at the exact same moment. Nor does it make sense that everyone would remain absolutely motionless with nobody falling down or dropping anything. When they wake up they have all been told that several hours have passed, yet they carry on with what they were doing before as though no time at all had passed.
Apostrophe mistake on the book cover in the tag sequence.
When the Classy Glass cleaners attack Steed in his car, they could have killed him but leave him unconscious. Jarret and Ferret are not so lucky.
After Tara and Steed have climbed down the ladder to visit Mother, a boom mic can be seen above them.