hello,
Here's my little 2 cents. All I know from this story is from this thread. I was not there and this is pure speculation.
Hypothesis :
1) "Show" performances aren't interesting. There are many way to cheat, even if you have no idea how. Do you know how the cut in half woman trick is done ? I don't but I don't assume that the woman was really cut in two pieces because I don't know the trick.
2) An illusionist want to give you illusion. Nothing is done by "innocence", all is about distracting you or doing something while seeming natural.
3) The story of the illusionist are pointless. He might say that he comes from 3 years naked training with dalai-lama. It's only part of the illusion.
4) When an illusionist compete under a false name in an AIDA competition, act like a crazy without knowing the rules and releasing a lot of bubbles, we will consider that he's cheating (for fun, for challenge, to test a new trick).
5) A magical trick is always easier than expected.
Thesis :
From 5), I reject idea of O2 bottle in the stomach and crazy stuff like that.
Here's the story. Mister X want to baffle the freediving community. What about a total unknown guy breaking a world record in his first competition ? Nice story. Mister X study a lot the AIDA procedure and watches video about competitions. Mister X also stops shaving his beard that day. Let say that Mister X is "quite good" at holding his breath, more than average.
The day of the competition, he walks in, under a false name, just in case someone know him by fame. He pretends not knowing anything at freediving. That's make him looking innocent. He ask for the WR and just look innocent while telling that he's slightly under.
He starts his preparation but he does nothing. He doesn't need t to do anything.
OT. He puts his face in the water. But only the face and not fully as the others. He stands on the bottom. From his mouth, he hides a very tiny snorkel. So tiny that it is hidden in his beard and, most of the time, it is immerged in the water. By moving and dancing, he creates waves. This allows the top of his hidden "snorkel" to get some air. He also need to stand very near the surface, hence the foot on the ground. Moving also allows to hide the noise of the air and to distract the attention of the jury.
Another possibility is that he's simply breathing in his beard. I've heard that it already happened that a juge heard an athlete speaking while still believing that the athlete was in the water. The noose was but not the full mouth.
Anyway, either technique don't allow you to breathe fully. It's harder and harder but, at some time, you have to gave up. Also, Mister X notes that everyone is now looking at him. Not something an illusionist want. The more he stays in the water, the more it is likely that someone will see his trick. Understanding that staying 3 minutes more with everyone looking is a no chance, he choose to stop the performance. While moving, he takes his "snorkel" and hide it in is hand (if any snorkel at all). Before surfacing, he take the hand of his coach and give him the accessorie.
Now, he does a little static but the trick was hard, he need air. To not look suspicious, he continues to have the face on the very edge of the water but he doesn't cheat anymore. That's the moment where people look the more closely and also the moment they will remember. If someone ever say he was breathing in his beard, judge will remember those last seconds : "no, he was close to the surface but I can guarantee he was not breathing".
He end and looks disappointed. That's more mysterious.
Do you think that this story is really impossible ? Certainly as much as cutting a woman in two or levitating, isn't it ?