What are the various loopholes you find in the story which according to you had helped Evans in escaping from the prison?
There were many such weak points in the security arrangements of the prison. The identity of the German teacher was never verified by any one from the prison. The identity of the feigning McLeery was also not verified, while coming and going out of the prison. Prior to Evan's exam, his cell was not properly searched and everyone blindly believed in Stephens. When he said that Evans had wounded McLeery while he was the actual Evans. Finally the Governor did not take Evans with him to the prison. Rather he sent him with a prison officer, whom the Governor might not have known himself.