No offense, but did you pay attention to what you read? Cause really, I don't know how you made this confusion, but she said 8'2" in height and three paces of width and depth, she was more than obviously talking about the size of the elevator and that girls who enter it are are her prey, she was basically describing her territory, or her hunting area, not sure how to call it.
Not gonna lie, I didn't immediately realise she was talking about the elevator either
It couldn't have been her height cus well, holy shit, but it still took me a minute to figure it out, oops haha
She also didn't look three paces wide, and as to deep, well...it's simply not that sort of manga.
Haha, I literally ignored everything else after seeing the height thing, my bad.