Earlier quoted context omitted.
This responsibility is to great to leave it to humans. Automate this stuff.
I think in the near term a possible remote override from air traffic control would make more sense.
That's a nice thought, but how would ATC determine what needs to be done? We are only finding out that this was an intentional act long after the plane has hit the ground. For all ATC knows, opening the door to the cockpit could be the WRONG action. If no one is responding from the cockpit, they have no clue what is going on other than the telemetry they are getting from radar and the plane's systems (which in this case wouldn't tell them much).
In fact, pilots are trained to communicate AFTER they have gotten the plane in a state to where they can either continue the flight or ditch safely if communication would distract them from the task at hand. ATC knows this, so even if they saw the plane dropping like a sack of rocks, they would probably assume that there was a problem and that the pilots are in a position in which a steep dive will help mitigate the problem (which can happen, such as depressurization).