According to the douchebag played by Ioan Gruffudd in the James Cameron-sanctioned Sanctum, a "Mongolian clusterfuck" describes what happens to a place after the adventure-mongering financier leaves it. And when Carl enters a place, here an unnamed South Pacific country whose fictional Esa-ala cave system has yet to spit out a human life through its much-coveted sea exit, it becomes the stage for what cringingly plays out like a community theater production of The Poseidon Adventure. Only someone who hasn't witnessed The Abyss would dare call Alister Grierson's film visionary.
Among the clusterfuck that has to swim out of Esa-ala's puzzle after Mother Nature makes the cave's mouth inaccessible: Carl's recently acquired arm candy, Victoria (Alice Parkinson); master diver Frank McGuire (Richard Roxburgh) and his buddy Crazy George (Dan Wyllie); and Frank's petulant son, Josh (Rhys Wakefield). Panic and arrogance is as much a threat here as the uncompromising, ever-rising water that clogs the cave system, but given the wafer-thin characterizations and half-hearted performances, Sanctum struggles to muster even a blip of existential dread. Hell, even the cave walls exude a plastic fakeness.
Though scarcely a character drama, Sanctum spends an inordinate amount of time stressing the frayed relations between Carl and Josh, who begrudges his father not for his incessant browbeating, but for the way his survival instincts fly in the face of common decency. Naturally, Josh ends up having to walk in his father's shoes and, subsequently, understanding the man, but after the umpteenth person has chimed in on the father and son's banally contentious relationship, you wish the film would just stick to the swimming.
Inspired by a near-death experience endured by director Alister Grierson while exploring a system of underwater caves, Sanctum's make-it-out-alive adventure is lamely jazzed up by the 3D format. The film dazzles during long shots of the cave-diving characters suspended in the Esa-ala's massive insides as if in utero, and though a character's heroic struggle for air in the end scans, however briefly, as a freakishly avant-garde cacophony of shapes, mostly the film makes an eyesore of the characters' frequently foregrounded backsides and the occasional glimmer of light that shoots past their heads and blindingly into our retinas.