Terror Train (1980)
1 plot hole - chronological order
Directed by: Roger Spottiswoode
Starring: Jamie Lee Curtis, Ben Johnson, Hart Bochner, David Copperfield
Continuity mistake: Kenny must be fast. He's disguised as the female assistant at one point then minutes later he's disguised in the Groucho Marx costume.
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Suggested correction: It's not a full costume. Kenny steals the mask and what looks like a small waistcoat (leaving even the hat). It's not implausible that Kenny made a quick change (probably after killing Ed) to formal wear (which isn't what Ed was wearing). After Ed's murder, Kenny-as-Ed appears briefly only from the waist up (showing only the stolen mask and waistcoat), and then doesn't appear again for quite a few minutes, more than enough time to change to the formal wear.