What would happen if you landed a 737 with an 8.5 psi differential pressure
You would not be able to open the doors in an emergency.
Saudia Flight 163 - Wikipedia, the free encyclopedia
"It took 23 minutes from the engine shutdown until the fuselage was accessed. Saudi reports stated that the crew could not get the plug-type doors to open in time.[7] It is assumed that most passengers and flight attendants were incapacitated during the landing roll or they would not have attempted to open a door on a moving aircraft. It is known that the aircraft remained pressurized during the landing roll as the cabin pressurization system was on standby and the aircraft was found with both pressurization doors almost completely closed. These pressurization doors should have opened completely on touchdown to depressurize the aircraft. The crew were found still in their flight station seats. The source of the fire in the C3 is unknown.[8]"