Leaving in the Dropping of the Duke's Coronet was a Mistake
1) Laurence Olivier and another actor drop the duke's coronet
2) Olivier fails to improvise a proper in-character reaction
3) As director, he decides to leave the scene in the film
4) He then decides to make it a running gag
He failed as an actor and a director in this instance. It was foolish to leave such a mistake, just seven minutes into the film. It takes the audience out of the film.
God loves filthy rags.