By being friendly and helpful and using his intelligence, he's able to become a trustee of the corrupt and heartless prison warden Samuel Norton, and enjoys several privileges.
The jail's warden, Lamine N'Diaye, told Judge Berman in a letter that the jail conducted an internal investigation into the July 23 incident, but did not say what the outcome of that investigation was.
He rushes into the tunnel, gets on the other side, breaks a sewer pipe, crawls through 500 yards of excrement, cashes in, exposes the warden to the media, and flees to Mexico.