Then I even more strongly recommend a cavern course. Yes caves/overhead can be intimidating and for some even claustophobic. For you it sounds more like an overreaction to a reasonable concern. Entering the environment for the first time with the knowledge and skills from a cavern course before you even get into the cavern may go a long way in preventing an issue before it occurs.I've been in dry caves and love it. I've been diving and love it but the idea of a cave in underwater where you can only watch your gas dwindle scares the bejesus out of me. If something shifted above ground you might starve or die of dehydration but you'll have time to find alternate exits or for a rescue to dig you out. It's probably total paranoia and given the lack of those kinds of incidents all in my head.
Then again you may float around the ballroom and think "this is really cool. I want to learn how to dive this safely." Your call.