The below is my proposed explanation that accounts for every one of those questions.
1 MB enters the SW doors under the awning area.
2 As she does, she is picked on cam, first by the cam noted as c1 which has a peripheral view all the way into the vestibule itself.
3 As she steps further northward up/down the main hallway, she is picked up by cam c2 which is looking over her shoulder.
4 Perp is lurking ahead, in one of the locations noted (P1, P2, or P3), having been seen by the cams earlier but not seen by MB as she enters and takes that stroll.
5 As she moves further up/down the hallway, per the arrow, the cam c2 loses sight of her movement and stops recording, and sometime shortly after that perp attacks.
6 Perhaps as he attacks, he pulls her out of the hallway. Perhaps she is first subdued then dragged to a spot, perhaps not.
7 Ultimately her body ends up in one of the places marked by an X, or maybe at P1 or P2 location, all generally in SW corner of the building's interior.
8 From any of those spots, an unseen-by-cam exit could have been possible out the kitchen door on N side of building, as LE believes.
