Revealing mistake: When the gentleman buying the dress comes out from behind the curtain in the change room, you can see the set for the canteen, with the lights off. (00:14:45)
German Week - S3-E6
Revealing mistake: When Mr. Humphries and Mr. Lucas make their toast with the German mugs, Mr. Lucas' mug breaks but Mr. Humphries' does not. A moment later, when Mr. Humphries notices the mug has not broken, you can see that he crushes the mug with his hand.
Continuity mistake: At the end of the show, after they reveal the 'new' ladies department. Mr Grainger is not wearing his glasses, as Mrs Slocombe has them in her purse, the shot changes to Mrs Slocombe, then back to Mr Grainger he is wearing his glasses, and there is no way he could have got them from Mrs Slocombe.
Answer: It usually just means seeing something weird or unusual, perhaps something someone wouldn't believe you saw without proof. The phrase is usually "haven't got your gun", although some people replace "gun" with "camera." Basically think about a hunter spending all week in the woods looking for the biggest [fill in the blank] and the one day he goes out into the woods without his gun and then finally sees it.
Bishop73