Agsain, those who see this as a contest still have not noticed that virtually every person who has given a depth went to that depth incidental to what they were doing--seeing something or doing something that was important to them. OK, you ask, important enough to die for--well--see the thread on how safe is safe enough--the answer is yes. I have done many things from flying to high speed motorccyle riding to diving that were potentially fatal. I am sorry that some see it as a contest.
The sinkhole is on the northen Gulf Coast. If you do some searching for sinkholes and submarine springs you should turn it up. It was a one time deal for me and it was in 1979 well before GPS. The skipper who took me there was a man I met diving out of Keaton Beach and he long ago passed away. I have no idea how those men found things with Loran and voodoo magic. I have been close to 200 on other dives but never that deep again. I only go deep when there is a reason. Just a few weekends ago I went solo to nearly 150 feet on the Kimberling City Bridge in Table Rock. A couple of years ago some friends of mine went to 190 feet. I did not go--why--it was cold and I saw no reason to risk it. They were fine and for that I am glad. Going below 150 feet can be dangerous, do not take the risk lightly but if there is a reason, something you must do, then I don't see it as a contest. There are reasons to go deeper, faster, longer, higher and for those who don't want to take any risks--don't.
N