alt Hacker News> Can it kill you? no probably not. The tension limit kicks in and lets the line out if you pull too hard.
Is there a physical safety? The anchors are attached to the wall, do they release with less tension than a human airway can withstand? I have experienced injuries that would prohibit me from exerting a "backpack" of force over my head.
There is a tension limit of 28 newtons on any single line. Beyond that, the motors release with a damped motion. This can be lowered, at the expense of payload capacity.