what happened here?

During a good manners and etiquette class being held for young children, the teacher says to her students:

"If you were courting a well educated young girl from a prominent
family and during a dinner for two you needed to go to the toilet, what
would you say to her?"

Mike replies: "Wait a minute, I'm going for a piss."

The teacher says: "That would be very rude and improper on your part."

Charlie replies: "I'm sorry I need to go to the toilet, I'll be back in a minute."

The teacher says: "That's much better but to mention the word ''toilet'' during a meal, is unpleasant."

And Little Johnny says: "My dear, please excuse me for a moment. I
have to go shake hands with a personal friend, whom, I hope to be able
to introduce to you after dinner. "