When the Gangster in the White Suit examines the oyster the girl has given him, it's obvious that the two shell halves are open almost an inch. This means the oyster has died and the shell is empty. Yet when the girl opens the shell, there's a plump oyster inside.
When the gangster tickles his mistress by placing the bowl of prawns in cognac on her bare stomach, the sound of her laughter doesn't match up with her mouth movement.
When the girl opens the oyster, she inserts her knife in the wide rounded end at the front of the shell. Oysters are opened by sticking the point of the knife into the hinge at the other end of shell.