In Theaters

“United 93”

Written and directed by Paul Greengrass, 115 minutes, rated R

Toward the end of the new Paul Greengrass film, “United 93,” the director delivers one of several masterstrokes, layering the hushed prayers of Christianity and Islam over each other until the cabin on that doomed Sept. 11, 2001, flight becomes a divided worship house roaring through the heavens.

In the theater, where speakers surround you in every nook, the experience of hearing Greengrass’ growing cacophony of “God” and “Allah” becomes almost otherworldly – a quiet chant.

Moments are undeniably melodic, as if the two religions, for an odd instant, create an unlikely kind of music, with the conviction of every soul on that plane joining a chorus to which they likely never thought they would be a part.

Like so much of this heart-breaking, beautifully handled film, you sit transfixed, knowing the tragic fate of the men and women hijacked by the four terrorists on United Flight 93, but not necessarily knowing what they went through during the final moments of their lives.

That’s still true – we won’t ever know. But by stitching together the telephone calls made by those passengers to their loved ones as the events unfolded – as well as the documented accounts of those in the military and air traffic control towers – the movie gives us a believable, realistic idea that is never sensationalized.

This sense of realism is heightened by a few factors.

First, the film is shot as if it were a documentary, with hand-held cameras giving it the claustrophobic immediacy and off-center sense of confusion cinema verite provides.

It was exactly the right choice, removing any sense of Hollywood gloss from a production that would have been bastardized by it.

Second, the film employs no known actors – the distraction of a Tom Cruise, for instance, thankfully has no place in this particular war of worlds – with Greengrass going a step farther by using several civilians who were actually there when the planes struck the World Trade Center Towers, then the Pentagon, and then when Flight 93 crashed into that stretch of Pennsylvania field.

Chief among those playing themselves is Ben Sliney, whose job it was as FAA operations manager to get a handle on the hijackings. His amazing “performance” – or reenactment, as it were – is a gift to history.

While the movie only ever wants to observe and never to pass judgment, which is its shrewdest move as it allows the viewer to remain firmly rooted in the moment and not in the murky waters of political commentary, it’s in its observations that it creates its gut-wrenching run of suspense.

Going into it, we all know how this movie will end, yet watching the terrorists enter the airport and take their seats among those they plan to kill nevertheless forms a knot in your stomach that becomes an anchor.

This is particularly true when the door to the plane is sealed shut. With the passengers still reasonably safe on the tarmac, just above them in the flight towers is chaos – frantic men and women aware of hijacked planes. The idea that none of this was shared with the passengers or with the crew allowed them to exist in a cocoon of false security. The world was learning fast that the world was on the brink of change, but for those in the planes, it was just another flight, a link to another destination.

Later, in the air, with the chaos unfolding inside Flight 93, the passengers and crew realized they had no choice but to unify and to charge into the face of madness. It’s a scene that makes the film the most difficult to endure since Mel Gibson’s “The Passion of the Christ” or Roman Polanski’s “The Pianist.” “United 93” presses hard on raw nerves and then, in its final frame, it literally crushes them. What Greengrass has created is haunting and unshakable, the medium at its full potential.

Grade: A

Visit www.weekinrewind.com, the archive of Bangor Daily News film critic Christopher Smith’s reviews, which appear Mondays in Discovering, Fridays in Happening, and Weekends in Television. He may be reached at Christopher@weekinrewind.com.