James Cameron lending producer cred to this film would probably pique your interest in it, but truly this film, loosely based on writer Andrew Wight's experience in cave diving and finding himself and others trapped in a cave, is nothing more than an average action adventure that aspired to be an edge of your seat thriller like Neil Marshall's The Descent, but minus the horror elements, trading that for more realistic Mother Nature type of disaster that threatens to drown out the adventurers.
As with most kinds of disaster films, a myriad of characters, often disposable, is requisite for that respectable body count. We have the billionaire Carl, played by Ioan Gruffudd, whose money funds the entire expedition in Papua New Guinea to explore one of the few unexplored deep caves for that bragging rights, as well as for that playground that he can use to bring chicks to for that big time impression. Alice Parkinson plays his moll Victoria, good looking and whiny, there as a thrill seeker. Technical experts are required, and the expedition is led by the seasoned deep cave explorer Frank (Richard Roxburgh) who possesses a no nonsense, pragmatic attitude toward one and all, and his estranged son Josh (Rhys Wakefield) who forms more of a bond with Carl than his own dad.
The danger comes in the form of nature pissing itself over the cave's large opening on the crust of the earth, and because the exploration is kilometers down and yet to be completed, this heavy rainfall no thanks to a typhoon means plenty of water come gushing through all orifices down the hole, trapping our adventurers deep down, and needing an exit before the waters rise and it becomes too late. This provides for plenty of set action pieces largely centered around slippery walls, deep water diving with limited gear, and claustrophobic caverns, coupled with enough gory moments like, of all things, clumped wet hair being trapped in gears, and more than one bloated water logged body.
You can expect the usual character development formed through plenty of bickering, especially when this becomes more like The Poseidon Adventure type of narrative as the characters constantly debate what's the next step of action to take, with Frank never being popular with his action plan, though they work most of the time. Throw a couple of moral issues into the story, such as euthanasia, yes really, where it's not about not leaving anyone behind, but rather sending them off in quite a painful manner so that their suffering from various extensive injuries, will not be prolonged. And this happens more than once in the film, which in my opinion will make you wince more than any other gory filled moments in the film will. And of course to make you examine if that option is something you would excise as well should you be in the same boat.
There's also a 3D version available, but this GV surprise screening was shown only in 2D, and that had clearly exposed very little, or no scenes designed that would have exploited its 3D depth of field, and none of those gimmicky moments with things shooting toward the audience. Cinematography was nicely done considering the nightmare water can bring to the table, and the deep water ones with contrasting light and shadows, though production sets do sometimes look a little cheap as if reshot quickly on the set in a studio backlot. Rhys Wakefield also puts in sufficient alpha-male moments that his role allowed (being the best climber in the group) which will likely propel him into meatier roles to come.
Sanctum is one of those films that remind you of a crucial element in handling emergencies, and that is to stay calm and not panic. A panic wreck becomes a nuisance and a threat, and in all likelihood won't make it through situations that require a level head to critically measure options available as solutions. A pity though that this film didn't live up to its promise and followed every conceivable rule in the formula book and had to rely on Cameron's big name as a crutch to keep itself afloat.