How can you prove that you are normal when you are mentally ill? Classic net Pick

Not long ago, a reporter named Grey Beck went to Italy to interview three special characters, the thing is this: A driver responsible for transporting mental patients because of negligence, halfway to let three patients escape. In order not to lose his job, he drove his car to a bus stop, promising to get a free ride. Finally, he took three of the passengers as patients and sent them to the hospital.
　　
Grey Beck is not concerned about the story, he would like to know how these three people to prove themselves, and thus successfully out of the mental hospital.

Here's an interview with him.
Gerry: When you were locked up in a mental hospital, what did you think you could do to save yourself?
A: I think, to go out, first have to prove that they are not mentally ill.
Gerry: How did you prove it?
A: I said: "The earth is round," This sentence is the truth. I think people who speak the truth will never be treated as psychotic.
Gerry: Did you succeed in the end?
A: No. When I said that for the 14th time, paramedics injected a needle in my butt.

Here's an interview with B.
Gerry: How did you get out of the mental hospital?
B: I and a were rescued by C. He managed to get out of the mental hospital and called the police.
Gerry: At that time, did you try to escape?
B: Yes, I told them I was a sociologist. I said I know the former President of the United States is Clinton, the former British prime minister is Blair. When I spoke of the names of the leaders of the South Pacific islands, they gave me a shot. I'm not going to talk anymore!
Gerry: How did C get you out?
B: After he came in, he didn't say a word. It's time to eat and sleep when you should. When the paramedics give him a shave, he says thank you. On the 28th day, they let him out of hospital.

Grey Beck in the comments that the feeling: a normal person to prove their normal, is very difficult. Maybe only people who don't try to prove that they are a normal person.

Later, many people in the text of the online version of the message. There is a person's message is very deep feeling: those who prove their truth in some way, those who prove their knowledge in some way, including those who prove themselves to be rich in some way, may be considered insane, but they do not know it!