Rules are rules guys..NO lights. They use them to communicate with each other as well as you. Actually you can use a small light, I can't remember what they called them but it would be small.
As for the guy going bonkers and not surfacing. Keep in mind that this is actually a underground lake. There are few times that you wouldn't be able to surface. When doing a swim through they are short, maybe 50 feet.
A buddy of mine has dove almost all the trails and they do get better.
There are a lot of things(ruless) in that article that don't exist anymore.