A joke in a mental hospital

In a mental hospital, dean wanted to try a patient whether well,asked him: "what you want to do after leave hospital?"
Psychiatric patients want minute and said: "I want to take a rubber band do a slingshot, then put the glass of mental hospital all broken."
Hence caught back treatment for two years.
One day dean find him to question: "what you want to do after leave?"
He think and said: "well personhood, find a good job and take a good wife..."
Dean asked: "and then?"
"On our wedding night,put the wife pants off, put the rubber band make a slingshot, put all mental hospital's glass broken."Then he were arrested back again for two years.
One day dean called him... "This time what you want to do after leave?"
He thoughtlessly says: "well personhood, find a good job and marry a good wife."
Dean asked: "and then?"
"Give birth a son..."
"After giving birth son?"
"... ask my son with a slingshot put all mental hospital's glass broken."