There are rescue vehicles that - if nearly everything is perfect and the sub hatches are not broken and jammed- could be flown that far south, carried to a rescue ship, get taken to the sub loss site, dive and maybe recover some of the surviors. Look up dsrv.
DSRV-1 Mystic - Deactivation begun on 1 October 2008.
DSRV-2 Avalon - currently at the Central Coast Maritime Museum, Morro Bay, Cal.
They have been replaced with remotely operated tethered SRDRS.