Apart from cranes, I seem to have done most stuff with a heavy camera strapped around my neck, and the worst I've done was a hyper-extension to my ankle following a mis-timed jump (Gunkan Apato Osaka).
It's been said many, many times before - prepare properly, know your risks and manage them appropriately. Being heavily safety trained & prepared for many years helps I know, so a few have an advantage there. But, the bottom line is if you do not know, do not take the risk. Which is of course the conundrum - how can you know what will kill you, without being told? What gas? What flaky steel? What glass roof? What sharp nail?
The easy answer is of course, the smart person makes the decision to not expose themselves, and the stupid person makes the decision to proceed and die.
Side-bar: In thinking about safety training, the only thing I've never really used exploring is my HUET. Anyone else similarly equipped with real world safety training? I love stories about sub-mariner evacuations. See ya! Neko.