On some aircraft, opening the cabin doors was part of the smoke removal process. For example on the 747, see the SAA 295 crash it was mentioned.
For the benefit of the OP as I recall it on the 744 getting any door movement was only possible once the aircraft had been deliberately depressurised (by the Flight Crew), and in theory the door handle was only moved far enough to open the "gates", the small panels top and bottom.