This is why I think fats need to be obligated to stay at those "pick up points" some places have.  We had that in one of my old, shit-tier jobs. The building was so old that we didn't have an elevator for staff (one floor only, but the fats still had trouble getting up the 20-odd damn steps), so we had a fire-retardant area with special doors and flooring at one end of the building for when we had clients in wheelchairs come in.  If a fire occurred, they were to go to that place and wait there for the fire department to get them. The fire department knew to go there and check for people, then proceed to the rest of the building as the able-bodied got out on their own.  We should have a similar law for fatasses who can't hoof it. They should have to stay behind and be last out, or stay in a designated area and wait for help.  Of course, fats being fats, they'd never listen.