Any other divers in the house?

For reference, a PADI or NAUI course is what, a week? And makes you qualified to go to 30m with an instructor? If you look at the dive tables you'll see that 20 minutes is all you get at 30m before you have too much dissolved nitrogen in your blood but that's okay 'cuz if you're doing a single-tank recreational dive you're going to use it all up in like six minutes that deep but honestly who fucking cares because nearly everything interesting - reefs, fish, recreational wrecks - are all within about 10-15m anyway so frankly that two-day intensive you take at the resort is likely plenty for your fuckin'-around-off-the-dive-boat vacation diving adventures.

But that's okay 'cuz they said my safeword:

It's easy to dive through the tunnel in the Blue Hole with Trimix or Heliox, but not with compressed air.

"Trimix is largely outside of the scope of recreational diving practices because it requires extensive training and equipment. For a basic class, for instance, you’ll have to meet the requirement of being an experienced certified diver. In terms of equipment, trimix requires a lot."

Trimix is cave-diver shit. Heliox is salvage-diver shit. Recreational divers generally live as long as anybody else, so long as they don't get too rambo on it. Commercial divers? murkier picture. I'll say this: when you substitute the air you breathe for a calculated admix of oxygen and helium, and then compress yourself to ten atmospheres, you're either aware of the stacked risk or blissfully oblivious to far too many indicators.

In Dahab, however, divers can buy depth. It's easy to find a guide who is willing to surreptitiously take a diver into the tunnel for €100, without asking unnecessary questions.

So yeah - like Everest if instead of having to train for six months just to get to basecamp and then pay $20k and wait for permits, you just pay a dude a Benjamin and... step off the beach.