(Pardon my ignorance pls.) Is the cargo compartment of a DC-10 pressurized, like the passenger cabin? If not, then the argument I gave above doesn't apply.
Oh, yes. Very much so. The floor on a passanger air liner cannot withstand pressure, so the entire tube is pressurized to the limits of the pressure bubble (space, not psi).
So if you lose a lower deck door, the plane is going down.