Opening doors in flight
It has been a while, however my recollection is that on the B747 the cabin smoke evacuation procedure called for both No1 and No 5 (L or R) to be cracked open to provide air flow through the cabin. Of course the procedure also called for flight below FL140 (to preclude the rubber jungle) and depressurisation of the aircraft. Never had to do it in operations, but the procedure was there.