How far it is to the way out, drawn on the plan — walking distance round the walls to the nearest exit, painted as a heat map.
Pick the doors people leave through and Egress measures every room to the nearest one — walking round the walls, not through them — then paints the result as a heat map with a legend and ranks the rooms by their worst corner.
Revit's own path of travel is asked the same question and shown beside each answer, which costs nothing and writes nothing. Reading the plan changes no part of your model; drawing the map is one named transaction, and Clear puts the view back exactly as it was.