Capt Pprune is correct on this issue we must look at ways of stopping this from happening again but not to the detriment of all other flights. A closed door is a barrier to effective crew communications and situational awareness, remember Sioux City there would have been much greater loss of life if the training Captain who was a pax could not have entered the flight deck to help! How would you deal with a pilot incompacitation if there was no flight deck access from the cabin. Lets be serious here and concern ourselves with all flights and all possible scenarios, we are in charge of the whole aircraft not just the flight deck we need access to the whole aircraft otherwise we might as well fly it via radio control from the ground.