He is at a loss for what to do and is about to go call a cab when he hears a shout from behing the hospital fence, where one of the inmates has been watching the whole thing.

"Hey, pal! Why don't you just take one lug nut off each of the other three wheels and use them to replace the missing ones? That'll hold your tires on until you can get to a garage or something."

Mr. Jones is startled by the patient's seeming rationality, but realizes the plan will work, and installs the spare tire without incident. Before he leaves, he calls back to the patient. "You know, that was pretty sharp thinking. Why do they have you in there?"