It's that scene from Robin Hood: Prince of Thieves where brave Robin (Kevin Costner) pulls out a dagger from his boot and stabs the evil Sheriff of Nottingham (Alan Rickman) in the chest.
We all gasp in horror as the Sheriff's mouth drops open in surprise and agony.
And then Connor exclaims sympathetically, "Oh no! He's going to need a doctor!"
I thought I would never stop laughing.