There was once a bus driver, and he drove a bus. It was no ordinary bus, however, since he was tasked with delivering mental patients from one hospital to another.
On the way, he grew weary and decided to stop for some coffee. Returning to the bus, he found it empty. The patients had escaped. "Oops," he says to his coffee.
He was a crafty man, however, and hatched a plan. He drove the bus to nearest bus stop, and allowed the people waiting there to get on.
When he arrived at the asylum, some of the people on the bus were banging on the windows and crying for help.
"These patients are especially violent," the bus driver told the hospital's workers. "They need to be restrained."
Several months passed. Eventually, everyone realized their mistake. But by that time, the bus driver had fled, and the unfortunate people who had gotten on the bus had become insane from their stay at the asylum.
The actual mental patients were never found.