Very well crafted thought experiment movie weighed down a bit by awful cinematography and editing and hit or miss acting (Brittney Snow and Jeffery Combs are standouts, while Sasha Grey is absolutely terrible). Not nearly as gory as it could have been, it is much more about the tension and vicarious experience of thinking what you would do in such an awful scenario. Very De Sadean, with an ending that is just an absolute kick in the nuts. I preferred this film to the directors later The Belko Experiment, even though Belko had better production values, because the concept is far more intriguing and the execution, no pun intended, is far more interesting and imaginative.