What all mistake done by the governor which finally made the evans to escape?
Answers
The planning of Evans was tricky and confusing. He knew that the police will be all alert and therefore, he decided something even more complex than the police expected out of him.
On the other hand, knowing that Evans had broken out several times previously, the police acted a bit clumsily. They could have tried to be more alert and observant. For instance, they could have constantly monitored Evans visually while he was at exam and not docilely given in to the demands of the invigilator. They should not have ruled out any possibility. They should not have allowed Evans to keep his "lucky hat" taking it very lightly as superstition on Evans' behalf.They could have been more alertly observant about the costume of the invgilator and cross-checked the phone numbers immediately and not just conjectured that all was in place. They could have confiscated the rubber like thing that the invigilator quite easily persuaded the officers to let him keep and which was later revealed to be a storage for blood. The Governor at the end knew how tricky Evans could get and so should have escorted him to the jail himself. Evans' trickery and playing-it-cool attitude along with such loop-holes in the Governor's plan helped in Evans' escape.
The major difference in their plans was that Evans plays a mind game while the authorities majorly look into physical possibilities of his attempt to escape.