There is no getting out at those sorts of depths as the pressure inequality between inside and outside of the vessel will mean you can't open a door or port, and even if you could doing so would cause explosive compression inside the vessel as water rushed in, killing everyone just about instantly.
Their only hope, if something catastrophic hasn't happened, is that they are either located and rescued from depth before their air/oxygen runs out, after losing mobility for some reason, or they are floating around undetected on the surface which will be a very hard search. A small needle in a very large haystack. I'd have thought the vessel would have a EPERB or similar for this eventuality and if so it means they aren't on the surface or it malfunctioned (which I think is rare) or they aren't able to activate it.