The reviewers below are criticizing the movie on the stage of realism which is unfair for any story as no story can get it right from that standpoint if they are being fair then they would have to criticize The Godfather, Game of thrones, Lord of the rings, The wire, The sopranos for those reasons as well.
Secondly, one of them criticizes the film for the star power of Clint Eastwood, because of the presence he adds to the scenes he is in cause of his inate nature, why is this a problem is beyond me as the character of Frank is established to be a charismatic character and someone with a commanding and authoritive presence and being the mastermind behind this escape justifies that not to mention he shows a vunerable side when he sees his friend chop off his arm.
Also there are steps involved besides the digging part did they even watch it.