Unfortunately the midspan latches had no such protection and were driven into the unlatched position enough for the internal pressure to rupture at that now weakened area leaving similar shattered door pieces and bottom latches still attached to lower sill for AI 182 and TWA 800. For UAL 811 and Pan Am 103, the soft, pre-AD, locking sectors were overridden by door motor and all ten latches were driven into the unlatched position allowing the door to open completely and slam upward, breaking in two and tearing away, leaving the identical pattern of torn away fuselage skin and door broken in half longitudinally at midspan latches for each door. AI 182 and TWA 800 had locking sectors hold so ruptures. PA 103 and UAL 811 had locking sectors overridden so entire door opened and came off. If the air keeps on coming into the balloon and less air escapes the balloon expands until pressure inside balloon exceeds strength to contain pressure.
Balloon pops at weakest spot on surface.
If air keeps coming into Boeing 747 fuselage with less air escaping, the fuselage will pop at weakest spot, a large door. Or if there is a small opening in fuselage, air may escape or air may enter from 300 KCAS airstream until door bulges out. If a hole appears in a seal of the cargo compartment, or a hole appears from corrosion, the 300 KCAS airstream might enter compartment and highly pressurize to cause door to bulge out the necessary small amount to allow a larger hole to allow more airstream to enter and the cycle continues rapidly until door is open enough for wind to tear it away. All the steel latches in the world are not strong enough to withstand 300 KCAS against a large surface door. If the fuselage is balanced in pressure and the aircraft starts to climb that balance is disrupted and the system attempts to compensate.