Interesting how I missed the sedation part till now. The way I rembembered it, they trained the boys to dive, right in the cave. But that must have been a plan that was later abandoned but stuck with me.
He basically told me one of many training astronauts have is in a long dark corridor that is submerged underwater of course to simulate low gravity. However the whole thing inside is wrapped in a plastic bag, for lack of better explanation. Just imagine huge condom big enough to fit people in it. When the shit goes down, you push emergency button and whole thing fills in with air in less than 90 seconds. Since its inside cave/corridor, air has no way to push the condom outside/up, so whole water is flushed out quickly.
He told me all they had to do is put a thick foil underwater, glue 2 sides together, making long sealed condom, and then pump the air in, making a way for kids to crawl through, with no need to dive or know how to swim, almost like they have those tubes on children's playgrounds. That's all.
What does it mean "glue 2 sides together"? Underwater? For 800m? Completely air and water tight?
Does untrained people be "confortable" to craw in a dark tunnel for 800m or the children would have freak out in the middle?
1. strong current messing with your construction
2. vertical sections and obstacles that will make your tunnel impossible to crawl through
3. corners, sharp outcrops etc. that might cause damage to it
4. sections that are too long for your construction to be stable even in good circumstances
If you managed to somehow solve all of the above with your design, you're still left with a construction job in an environment where people died just trying to traverse it.
There's like a myriad reasons why this is a bad idea and will much more likely result in awkward failure or even death instead of a success.
Let's not even talk about getting this assembled out of sturdy-enough materials before everyone is dead anyway.
And even if you manage that: One tear in that construction and you can guarantee the death of any child still in it.
If I had to choose I'd go with the professional cave divers and on-scenes experts rather than the dreams of some guy a thousand miles away with questionable, hardly-relevant credentials.
Which sounds like a great recipe for panic and death.
And if you're protecting for that (e.g. by walking through the tube with breathing equipment), you're just making the situation more difficult and less like anything anyone has experience with.
Given that:
a) there was continuous pumping to remove incoming water that would be overwhelmed if there was additional rain,
b) the location was remote,
c) "pushing the water" out would have flooded the location where the boys were when the non-existent tube was inflated,
d) the path to the boys was so treacherous that one very experienced diver died while replacing oxygen tank replacements,
e) after the last person was rescued (the coach), the Thai and other divers still in the cave almost died as the pumps failed while they were making their exit, and,
f) no such "thick foil... making long sealed condom" was either available locally or offered by anyone.
In other words, typical "Monday morning coaching".
Several options have been duly considered and politely dismissed. The kids won’t be confined to airtight metal coffins, as Elon Musk has proposed, or made to crawl through a several-kilometres-long inflatable bouncy castle tube, as one Bangkok construction company suggested.
The plan they enacted, even if it might have had a lower chance of success (and I don't know that it did), was much more resilient.
One of the really important things the article explores in detail (but never calls out explicitly) is how many backups and fallbacks there were. Air tanks spread across the whole cave, multiple support stations with extra people. There were many opportunities to adjust to changing conditions. Even if getting one kid out went wrong, attempts at rescuing the others were mostly independent. All of this adds up to a pretty damn good chance of at least partial success.
That's not how simulating low-gravity works. You need to be in the water yourself. You can't be in a pocket of air underwater for that.