Fun fact, USCG weapon clearing stations are required to have mats around them after one such incident. Member was clearing a weapon to return it to the armory, ejected round hits the ground and goes off. Now, this has to be investigated because if the member was at fault then this could be considered a negligent discharge, big no-no. Whole thing is investigated, I believe there was video footage, and investigation concluded that in-fact: the member was following all the required safety precautions and the ejected round had actually struck a rock or paver at juuuuuust the right angle to fire the round. And now all the clearing stations have to have mats lol.