Help with SHOULD+have+pp

[ARUK2008]

I have to create a very short story to tell my students or to create some other way to start the lesson.The sentence that I have to use as the ending is:

"He shouldn’t have insulted the policeman."

I've written a dialogue but I think it'll be boring for them.
A man went to a costume party, dressed as a police officer. After a couple of hours and some drinks, he caught the attention of a guy who asked whether he was really a police officer. He burst out laughing and said, "I'm not stupid enough to be one," to which the other man replied, "That's good to know. I am a policeman."

[Tdol]

It does the job