Honestly, this story is the reason that I try to find all the threads where novice divers ask about the cenotes, and tell them it's a bad idea to do the tours until they have enough experience to know how they react under stress. It sounds as though you were uneasy from the beginning because of the gear problems, made more uneasy by your inability to get a response to your signal (which is one inexcusable thing on the part of your guide) and by being off the line (a second inexcusable action on the part of your guide). You may have begun to breathe shallowly, and then CO2 snuck up on you and finished the slide into panic. You were extremely lucky that you were under an air pocket -- there are many points in those cavern tours where there is NO option to surface. The essence of overhead diving is the ability to maintain your poise and cope with whatever happens without going up.
I remain concerned about the guide's part in this, though. How many of you were there? One of the reasons the groups are supposed to be kept to four is so that a guide CAN see the signals from the last diver, as one cannot depend upon the team to pass the signal up the line, as trained cave divers would do. And when you say you were off the line, how far from it were you? Could you still see it?
Cenote tour operators are self-policing. There is a class which they are supposed to take (although there is no regulation to require it) and there are rules by which they are supposed to abide (but again, this is voluntary). I have seen most of the rules broken down there, with ratios greater than 4:1, no lights on some of the guests, and leaders in single tank setups. It is truly caveat emptor on guiding.
I remain concerned about the guide's part in this, though. How many of you were there? One of the reasons the groups are supposed to be kept to four is so that a guide CAN see the signals from the last diver, as one cannot depend upon the team to pass the signal up the line, as trained cave divers would do. And when you say you were off the line, how far from it were you? Could you still see it?
Cenote tour operators are self-policing. There is a class which they are supposed to take (although there is no regulation to require it) and there are rules by which they are supposed to abide (but again, this is voluntary). I have seen most of the rules broken down there, with ratios greater than 4:1, no lights on some of the guests, and leaders in single tank setups. It is truly caveat emptor on guiding.