I'm being a bit dull here and can't get my head around it.
But. At altitude, the reason why everything gets sucked out is the cabin pressure is higher than outside, so if for whatever reason, there is a breach in the hull, it would mean the high pressure of the cabin would flow to the low pressure outside right?
So if on the ground, and the aircraft is still pressurized for whatever reason. Wouldn't that mean the pressure outside the aircraft is MORE than the pressure inside the aircraft? So wouldn't it then flow in the reverse direction?
I know that if you open a door when it is still armed however, you will get a very different response!