kc_moses - As a public safety diver, and someone who has both the TDI/SDI "Solo Diving" certification and the PADI "Self Reliant DIver" certification, I would suggest that if you have questions about the buddy sytem, perhaps you should think about getting additional training and redundant systems so that you don't have to rely on a buddy to save you. Ultimately, you are responsible for your own safety. That extends to making sure that your gear is instact and working properly and has been properly serviced, you have the skills to take care of yourself, and most importantly, you can stay calm in an emergency situation. There are some things that can't be controlled, and you may need help someday, but there is quite a lot that can be done to minimize those instances.
Sorry for the diversion, but back to the topic at hand, like Tim, my heart goes out John's family, friends and the divers and crew that were there that night, and have to deal with all this. This is a sad situation, and it will be very informative to hear the final conclusions about the cause of death, if there ever is a determination.