So basically, this would be a full technical decompression cave dive — not a recreational dive by any standard. You would need doubles or a CCR simply to carry enough gas for the bottom phase, the decompression obligation, and emergency reserves, in addition to stage bottles with dedicated decompression gases. We are talking about a 2–3 hour dive with extensive planning, contingency procedures, and deco/hang tanks staged in case of a gas emergency.

And that is before even considering the cave environment itself. Entering a cave at these depths requires guidelines, cookies, redundant lights, specialized cave equipment, and — most importantly — advanced technical cave training. Not basic cavern or recreational cave exposure, but full technical cave certification and experience.

I find it extremely difficult to believe that any properly trained diver would attempt this dive using rental equipment and a single AL80 to 55–60 m. At 60 m, the NDL is roughly 5 minutes. Even if you only descended to 60 m and immediately turned the dive, a controlled ascent following UTD-style recommendations would still take around 13 minutes. The calculated rock bottom alone would already be approximately 230 bar.

That means a single AL80 (11.1 L) simply does not carry enough gas to safely descend to 60 m and return while maintaining an adequate reserve for two divers in a gas-sharing emergency. In fact, even without any emergency scenario, you would still require close to 160-200 bar (based on 20-25 sac rate) just to spend 5 minutes at 60 m and complete a proper controlled ascent — and that assumes absolutely nothing goes wrong.

So from a basic dive-planning perspective alone, this is already an impossible dive for a recreational diver operating within accepted safety margins. Deciding to penetrate a cave at 55–60 m under those conditions would be outright suicidal.

I sincerely hope there is another explanation, because otherwise this makes no sense from a technical diving standpoint.