"Fools rush in (again) 411A.
Doctors said that about Thalidomide when it was released as a sedative!!
Assuming our "Sky Marshals" Buck and Roy Rogers) were NOT such "Dead-eye Dicks" - and obviously in this case they weren't, as a steward was wounded - and a couple of stray bullets entered the pilots' bodies. Remember, that cockpit door is double/triple latched from the INside.
I agree with the end result obtained in this case, but the weapons need further refining.