Starting with the disclaimer that I guide "purely recreational divers" into overheads (caverns and lava tubes) for a living, I will agree with others that not mentioning the overhead in the briefing was a mistake on the dive guide/operators part.
A few Q's; how many dives had you done with this dive guide prior to this dive, how many dives had you done with your wife prior to this dive, how many dives have you and your wife made??? Seeing that you joined SB in '03 I'm assuming you are not inexperienced divers.
Now that I think about it, there are more Q's, like; how did you spend 12 days of diving on the same dive boat with just 2 dive guides and their dive certification levels never came up in dive conversation, did the dive guides know your certification level and dive history, are you and your wife using your own well maintained reg's and finally for anyone following this thread, when was the last known reg failure on a dive of a similar profile???
I am only familiar with PADI and IANDT recreational diving literature, so I can only state that while those agencies have wording
similar to "NEVER, EVER enter an unfamiliar overhead environment
like that without training and equipment" It seems to me that your paraphrased statement does not exactly convey the same meaning as the actual printed word of
any recreational training agency, which might be part of the reason for the silence following it.
Did the guide know what your tank pressure was? When talking with the other group about this "cave", was this other exit near the surface how they ended the dive? I will reiterate that the briefing seems to have been too brief, but this sounds like it could have been the ascent.
Finally, have you ever followed any of the guided cenotes threads? This recent thread concerning
inexperienced divers in a guided overhead situation has a very worthy first reply.
http://www.scubaboard.com/forums/mexico/263698-cenote-diving-inexperienced.html
Man, it's so hard to say what I'm going to say, because I'm a cave diver and cenote tours before I took my classes were what got me hooked on caves. But I have to say it: I don't think very novice divers belong on the cavern tours (although they routinely do them). I base this on a couple of things: One, as a very novice diver, you have no idea what your reaction to any kind of problem underwater is going to be. An overhead environment is not the place to discover, as a friend of mine did, that flooding your mask unexpectedly is going to make you panic.
Once you have done a bit of diving, and had an issue or two, and know you can remain calm and organized you're far safer in a situation where you CAN'T go to the surface. Secondly, most novice divers have marginal buoyancy control and often have poor trim, and the beautiful cenote environment deserves more respect than that.
If you are determined to do the tours, I'd highly recommend seeing if you can find some overhead trained divers to do a few dives with and get some solid help with your buoyancy and trim. You might find some resources
HERE.
I too find myself in the rare position of nearly complete agreement with String
diver with less than 10 dives
55' deep off Lanai, Hawaii
(holding on to the
lava rock is part of the briefing)