Thank you for your explanation.. Doors with an interior push bar are supposed to lock when pushed shut. She would have no way of testing the door to see if it was locked after she moved the rock unless she tested it from the outside.
Unless it didn’t close all the way and latch. Or it was broken.
The shooter may have gone to that specific door because he saw the teacher run inside that door.
What are you talking about? You can push on the door from the inside to make sure it locked.