Why are prisoners so afraid of going to "The Hole"?

Question

At least they're hole would be safe during that time and they wouldn't have to worry about getting shanked. Light and sound deprivation, are factors, but still.

Answer 1

They are sick people and who knows they may be afraid of them self.

Answer 2

Because humans thrive on social interaction. If someone is shut in a hole and had no communication with anyone or the outside at all for a lenghthly time the person could go nuts.