The pity is we keep repeating the same mistakes in cave diving because we forget the past, and there is an unfortunate end result. For example, the one certification level that has had most accidents (not medical issues, but true cave diving accidents) is the intro level, and this has come from this group stepping outside their level of certification. For example some accidents over the last few years will show visual jumps, DPV use etc. I think intro is a great certification, and history shows if you stay in the limits, it is safe, but exceeding these limits has negative consequences. Hence, taking an intro certified diver into a full cave situation for another class is not well advised.