Well I am not in the medical field but I would bet everything I own that the cause of death will be drowning. There may have been an underlying heart issue brought on by panic but the guy drowned. The ME will not come out and say that the 2 didn't run a reel, the intro diver was tagging along with a full cave diver who is an instructor so he felt safe and that when the crap hit the fan they both pannicked and the full cave diver left his buddy for some reason. Just like in the Eagle's Nest incident the guys were doing a dive they weren't qualified for. There is a big difference between qualification and certification.
The short and dirty of it is no one will publish that or do accident analysis because it is bad for business. In the industry there is a big push to sell certs and gear. When you see divers who have only been ow certified 3 years and now they are cave diving with scooters and rebreathers there is an issue but it won't be addressed because people put money first and turning out quality divers second.
Someone can tell me I am wrong but as technology keeps increasing and it becomes easier to do these dives it will become more common place. All the money and gear in the world can't supress fear and panic. The only thing that can do that is experience.
As long as the agencies keep ignoring this and blame it on stuff like the line in the EN incident nothing will change. Hold the instructors accoutable for cranking out certs.