Good question. "Out of range of the camera" isn't about their field of vision, strictly speaking.
It's about a characteristic of those cams that LE has noted and that we see in the other videos, which is that they would trigger to the on position when they detected movement, and they would trigger to the off position (and stop recording) when they didn't, and as you move farther away from them, the less likely for the camera to detect your presence/movement. So we see in the released video that as perp moved down the hall away from the camera, he suddenly vanishes into thin air, and then when he comes back he reappears from nowhere, even though it's still within the sight lines of the camera strictly speaking.
Like I said, not only do we see that in perp video, but LE has mentioned it.
So from what LE says, it's the same thing with MB. At some point in the main (ie west side) hallway, as she's walking away from the cam, it stops recording. We do know that the "disappearing act" happened in the broad "vicinity" of where her body was found, so it's logical that the cam shuts off somewhere SW-ish, and I have drawn my map to reflect that (with the red X's denoting potential places where her body may have been found, places with no cam).