Saul's Behaviour
The style of close-up filming worked for a few minutes in the beginning, then just became annoying.
Saul may have been insane, but I found most of hs actions so reckless, so self-centred and so ridiculous that it ruined the film.
He wandered into areas that were off limits, grabbed people or clothing with guards around, lost the "package" that was supposedly integral to their plan, hid the body, dug a grave, argued with others, and generally was so unreliable and risked eveyone's life so often it was implausible any other prisoner would even care about him, let alone help him, rely on him or try to help him.
In the situation they were in - he was a total liability.