When the girls are explaining how they plan to get into Knox Technologies, one of them says.. "the floor is rigged with pressure sensitivity..any contact that exeeds point-two five seconds will sound the alarm". That's 0.25, not 2.05 seconds. It takes a person that long just to mentally regester and react. By the time she hits the floor and begins her next flip she's already spent too much time. Even as thin and light as she had to be to be an angel, Natalie couldn't have managed to flip that fast. While she's preparing for the next flip, the time is just ticking. And on top of that, to be invisible to the camera beforehand she'd have to put on the white suit before she went in. Undressing in the chamber would look really suspicious. Theres also that whole for her eyes, which you would still be able to see. And if you count her flips, they actully seem to last about two seconds anyhow. Gee, oops! Either somone screwed up their line, or the alarm was broken.