Intruder,
The reason for the blow out panels and press equalising vents throughout the a/c is the Paris DC10 aft bulk cargo door failure. These panels are certified to cope with a cargo door blow out at max diff, 9.4 psi on the B744. The DC10 was lost because, in short, the rear cabin floor partly collapsed and severed/disabled the flight control cables. no FBW in those days, just good old stainless cables.