Director Paul Greengrass’ United 93, his interpretation of the remarkable airline passenger uprising against Sept. 11 terrorists, is an extraordinary film about the nightmarish final moments for the people on that flight. No telling of the story could ever be 100 percent accurate, but Greengrass and his crew have come up with something heavily researched and respectful that stands as a moving and deeply disturbing depiction of unity when faced with tragedy. Filmed with the same documentary look that made his Bloody Sunday so effective, Greengrass tells the story in something close to real time. The film points no fingers and puts no blame on political figures or the government for the events of Sept. 11. It can’t do that, because events are depicted strictly in the moment, when nobody knew why planes were disappearing, one after the other, off radar screens. This is not a movie to be enjoyed over a bag of popcorn and bucket of soda. It’s one of the more painful movie experiences in the history of cinema, and it should be.