I wonder if anyone has details on the dive site. I find it hard to believe they entered an actual underwater cave (by the definition we normally use) on a dive to 60 meters. That would be a very serious technical dive. I assume (hope???) it was a swim-through or arch that should have been easily entered and exited.
Just going to 60 meters, with or without an overhead environment, is a serious dive. If I am going that deep, I am going to be wearing full tech gear, breathing trimix, and carrying at least one decompression bottle. Is this dive done with single tank recreational gear? (Yes, I know that is done in places.)