Interesting, where I volunteer (a large public facility) our instructions are to get those unable to use stairs to the stairwell, if possible get them out w/ the special stretcher/chair located in that area, if not possible to use the stretcher/chair, get the most people you can out, but leave any you can’t in the stairwell w/ the fire rated door closed & of course when you report in at your designated spot advise of the location of those still in the building.
Thus, I’ve always assumed that most stairwells in modern buildings have fire rated doors and are the safest places to wait for rescue.