There seem to be two scenarios under consideration.
A. They're trapped or stuck down below, in which case they're sadly toast as that's as no one has assets available that can get to them anywhere near in time, never mind attempt a recovery, even if the missing sub is located swiftly.
B. They've surfaced for some reason (for example, in the event of a power loss the sub will autorelease its drop weight and it will rise to the surface using nothing more than physics to do so), in which case it's a big-ass ocean but with any luck will be found.
Either way, a news story that doesn't involve war or politics is certainly interesting, although one must not underestimate the peril in which those good folks may be.
If, perish the thought, this has an unhappy ending I can see the authorities banning such 'tourist' visits to the wreck site.