On opening windows during a hazmat fumes situation and or maindeck or cockpit fire, I am aware of at least 2 incidents(not accidents) where a window was opened. Procedure strongly discourages this but in the 2 cases it worked. Both cases were at the Flying Tiger Line, one in the late 1960's and one in the 1970's.... The involved captains told me that the checklist items had been accomplished and the situation was still pretty dire. And both captains said that it was a result of the following thought loop."Well that's every thing in the book, and things look like we are about to die so does anybody have any more ideas?" The window opening enabled a landing, make note that in both situations the aircraft involved were close to landing when the window was opened. There is no "window " to open on a 744 and how the escape hatch or smoke evac port would work might be quite different. Food for thought