As Elena straps on a SCUBA tank to go after the blood, Porter tells her that she can't make it as the water is 300' deep. At that depth, the pressure is approximately 10 atmospheres or 147 pounds per square inch. The container and its contents would have been crushed like an eggshell.
The helicopter is a Coast Guard asset, including "USCG" emblazoned on the underside of the fuselage. But the closeup of the pilot shows him wearing a Navy helmet.