I knew I was lucky, when the building beneath my feet gave way while doing a large hotel demolition, and I somehow landed on my feet and then rolled without getting jabbed by any of the six inch spikes that were protruding from piles of salvaged
wood. Banged up but not punctured, I resumed work about an hour later, but could still feel some sore spot 2 weeks later. About a 10 foot drop.
Fortunately, I have had the good sense to not show up at any of my brothers jobs since then. Incidents like that do not happen at my own jobs. They had undermined the area and not marked it in any way, before my arrival. Some of the guys knew that you couldn't walk there and some were oblivious, as I was.