[gloosx]

>we could imagine someone holding their breath until they pass out and fall.

It is not easy to imagine this. Brain have protective mechanisms in place to prevent this. If someone is holding their breath for too long - they start experiencing an immense, primal fear which magnifies tenfold every second. It is close to impossible to consciously bear that fear and continue holding your breath – every other second requires years of practice. You will inhale, if you can. Your body simply wont let you fail or pass out.