I have been watching videos most of the day:
I found out where they are talking about the door closing. If you watch the video above. At the top of the of that first roof area, this is the only white area, right next to that is the door, after a couple of shots the closes, but not all the way. To me it looks likes the movement of the building causes the door to close.
Here is the building from the back side. At about the 11-12 second mark on the video a bird flies right about the 13th floor. Since this is the backside, from the front maybe it looked like some movement. I don't know, when I first watch it, it caught my eye.