Mother Frances warned us about that door when she visited our class during the first week.
We were not to open it, and we were not to go down the fire escape unless a fire alarm had sounded. She made clear that the fire escape was dangerous, we could get hurt, and she would “thrash us to within an inch of our lives” if we were caught there. Apart from that warning, she seemed mellower than she had when she addressed our coed class the year before. This confirmed our suspicion that her dire warnings really were intended for the boys. Corporal punishment was not much in evidence during my year in the third grade.