Factual error: When Christina mixes a drink for one of Mommie's "guests" she bends down behind the bar to put a bottle back. Sitting on top of the bar is a Trigger Sprayer bottle of "Fantastick" - a spray that did not come out until the late 60's.
Factual error: At the end of the film where the blinded Michael is swinging his scalpel aimlessly, it makes loud "swooshing" sounds. This is pure fantasy. I have personally mimicked what Michael did using similar small scalpels and even larger knives without almost no sound when swinging them.
Factual error: Though it's set in England, hospital personnel use American terms like "charts" and "orderly". In any British hospital these should be "case notes" and "porter", respectively .
Factual error: The rifle which Dennis Dugan's character is using has to be reloaded before every shot. Still, when he shoots Slim Pickens, he somehow manages to hit him with two bullets within a second.
Factual error: Right after the opening credits, captions say "Susan's house - 1961." And right afterwards, the model train runs by two cigar boxes, one of Dunhill n.25 (seemingly one of the later designs of the box) and the other of "Joya de Nicaragua", a brand founded in 1968. (00:01:25)