After the stage where she closed the door with a parent in the room, she moved on to going into her room on her own and closing the door behind her. She isn't tall enough to completely reach the door knob; she can only grasp at it without getting her hand around it. So, she would go into her room, close the door, and a few seconds later, I would hear soft knocking. She has never panicked at all. She just stands there and knocks. I usually go to the door and knock back before I open it just to see what she'll do. Then, I turn the knob and push the door just slightly so as not to smash her feet. As soon as she sees it is partly open, she grabs the edge of the door and pulls it open the rest of the way. This picture is her making her exit after just such an event. (I have to add here that the huge mess behind her is due to the fact that she hasn't had a closet since January. Our "home improvement" project did the opposite for her situation, although my kitchen sure isn't complaining.)
Then, it happened. She went into her room and knocked. I came a second later to release her, knocked back, put my hand on the knob, and turned (I mean tried to turn) the knob. It didn't turn. She had locked herself in her room! I tried not to panic. Luckily, the previous owners of our house had had a roommate and had keys made to all the doors and dutifully turned over all those keys when we bought the house. . . it was just a matter of finding them. So, I grabbed the phone to call Grant to tell him we might have a problem while I searched through one of our junk drawers for keys. I was standing at the door with a handful of keys, trying each one and narrating to Grant on the phone each time one didn't work, listening for distress behind the door and trying not to picture her turning up her heat and not being able to turn it down or climbing something (I don't know what, but she'd find something) and falling and hurting herself. Then, after 3 or 4 keys that didn't work, the knob turned. She had let me in. She was perfectly calm and unaware of any reason I should have been worried. Though the door was open, I continued trying keys until I found the ones to her door. They are now easily accessible just in case of a repeat. Whew!