Sanctum is one of those films that you hope will be awesome. It has all the potential to be a beautifully photographed and suspenseful underwater adventure; unfortunately, it loses its mojo straight off the bat. The film plays out like a typical adventure film, complete with life-and-death situations -- in this case, broken oxygen tanks, cave-ins, decompression sickness, and hypothermia. At times, though, it feels like you're watching one of those educational films that you'd see on an elementary-school field trip to the science center, and at others, much like the winding caves in the film, there seems to be no end in sight. For a film that's supposed to be a thriller, there aren't that many thrills (aside from the occasional gross-out moment), and when all is said and done, you're kind of glad it's all over.
The story takes place at the Esa-ala caves in Papua New Guinea -- the largest unexplored cave system in the world -- where master diver Frank McGuire (Richard Roxburgh), joined by his reluctant son, Josh (Rhys Wakefield), explores the caves. But when their exit is cut off in a flash flood, Frank's team is forced to swim to an unfamiliar cave system. With dwindling supplies, the crew must navigate an underwater labyrinth in a mad dash to make it out alive.
Director Alister Grierson creates some intensely claustrophobic moments involving narrow caves, falling rocks, and underwater tunnels that stretch on forever, yet at its core Sanctum is a story about a relationship between a father and son. Josh comes across as a whiny little brat (even in his most heroic moments), but Frank is the most engaging of the pair. Richard Roxburgh expertly portrays the hardened explorer who wants to survive. He takes care not to let Frank tip too far into clichéd territory (like most of the supporting characters), and despite the fact that he's sort of a hard-ass, he's still the most likable character.
There's a certain level of expertise involved with the making of Sanctum, and that may be due in part to the participation of underwater explorer, filmmaker, and screenwriter Andrew Wight, who worked with executive producer James Cameron on his underwater documentaries Aliens of the Deep and Ghosts of the Abyss. Wight's expertise is reflected in the script, and combined with Cameron's hand in the 3D technology, both lend a sort of credibility to the film. Still, even if Cameron's name alone is enough to fill the seats, this isn't a "James Cameron picture," and for all the attempts at creating a suspenseful thriller, Sanctum just can't stay afloat.