In rare occasions an out of battery detonation can happen and be a real show stopper.
Check out this video from YouTuber MaewNaam Arms and see it caught on slow motion video.
While shooting this auto-loading shotgun this shooter had quite a rare but very scary occurrence, and out of battery detonation.
So what actually happened? It appears the brass rim of the previously fired shotshell impacts the live primer of the next shotshell. The bolt has yet to close and the live shotshell detonates in a spectacular way.
Luckily it appears no one was hurt but fellow shotgunners take note as it indeed is possible as proven on this video. Be careful out there and have a (shotgun) blast!