@Roberta,
I never would have guessed it if you hadn't mentioned Lean. I was picturing a little person using the knife as a mirror.
Late forties.
At her husband's urging, she dances a sultry Latin number with their new employee. She suddenly realizes that she and her partner are exhibiting too much emotion, actually passion, in front of her husband, and stops dancing. She quickly walks over to the jukebox and pulls the plug.
