Gentlemen of Leisure - Have you ever seen this happen at the gym?

You have no idea of the stupidity that I see on a daily/weekly basis at gyms. Worst I have seen was while working the late shift at a world gym back in florida a few years ago. Just me working the front desk, 2 chicks doing cardio and a Big guy was doing 120lb dumbbell presses who could easily do em for 12 reps, got to his second set and about halfway up on a press the right dumbbell just falls onto his face, knocks him out cold( i thought he was dead to be honest). I have to call 911, im not cpr certified at this time so Im going crazy, have no idea what to do. You could look at his face and tell he cracked his skull, it was pretty bad. About a week later somebody who knew him comes in, come to find out the guy tore his peck mid rep and lost controll of the weight. Never saw the guy again, dont know if he ever lifted again. Whats the moral of the story?? ask for a spotter!!!