Modern Warfare Styles!... partially. Get some men on board!
On a less crazy sort of note. Why not shoot the cockpit out? Sure it will de-pressurize the cabin, but probably only for the cockpit, and there's got to be a point where the plane get's low enough that a civilian can try and take over? Even if not, and you've shot everything to shit, and it's unrecoverable, you tried your best and saved the lives of 10x the 747 population. Not to mention the auto-pilot might survive, buying you far more time to get people off the plane.
On a less crazy sort of note. Why not shoot the cockpit out? Sure it will de-pressurize the cabin, but probably only for the cockpit, and there's got to be a point where the plane get's low enough that a civilian can try and take over? Even if not, and you've shot everything to shit, and it's unrecoverable, you tried your best and saved the lives of 10x the 747 population. Not to mention the auto-pilot might survive, buying you far more time to get people off the plane.