Then why continue out to the sea? Were they hoping to dump only to discover that the pumps were also done in?
Just imagine sitting at the front end, levelling off at FL300, and discovering that no one is talking to you. Maybe a couple of warnings ringing at you. How long would you think it would take to find out the satphone is working? And then: who will you call? And after you might have found a number: the guy on the other side will have to find someone who can help you. The one who can help you might not be the one who owns the airspace you´re currently in. There might be other traffic around you in busy airspace. All while travelling eight miles a minute. Might not have been such a bad job by everyone.