He knows this and is nervous while changing the tire.
It doesn’t help that one of the patients is watching him from the other side of the fence. The guy drops two of the lug nuts and can’t find them. Starts to panic.
The patient speaks up: “Just tighten up the remaining two opposite from one another. Should last till you get to a gas station.” The guy thinks about this, does so, and straightens up. “Pretty smart….uh, what are doing there ?” The patient replies “I’m here for being crazy, not being dumb.”