>>6346Because the "at first" part lasts a really long time.
Each gasp of air you manage to get prolongs it, and believe me your whole body will be in revolt trying to save itself.
While you feel the urge to breath within 2-3 mins of stopping breathing (significantly shorter if struggling) you won't actually pass out until long after that. And then each gasp resets the timer, but not the pain. Furthermore during the whole experience your perception of time is skewed, as everything was slower. 10 seconds minutes to pass.
If you're going to do it then you'll want to do something that completely traps you beneath the surface with no get-out mechanism. Like handcuffing yourself to something down below.
If you do handcuff yourself then expect to break some bones trying to pull out of them. You'll feel the pain but it doesn't stop you acting as it normally would, you'll use every trick you know to crush your hand/wrist bones in the hope of escaping.
If there is something sharp on you then you're gonna have a bad time.
I know it seems that you can simply decide not to, but you can't. You'll be flooded with an undeniable NEED to survive that you can't do shit about.
A knife between ones ribs into the heart could be inserted before the pain kicked in. There's also pain to deal with here, but not the mental aspect of the struggle.