With water rushing around them, sailors aboard the beleaguered USS Fitzgerald faced an agonizing decision.

They had made several rescue attempts into the flooded portions of the 505-foot destroyer, which had collided off the coast of Japan with a much heavier container ship early morning Saturday. But they didn’t know how many of their fellow shipmates were still trapped inside or even alive, and time was running out.

The sailors either had to close off the flooded areas of the ship, or they feared the entire destroyer might go down, according to three active or former members of the Navy familiar with the incident.

They decided to seal the doors.