Buckshot and Slug Shells exploding outside a gun - Are they deadly?

What happens when a shotgun shell accidently goes off outside a gun? How dangerous is it? This is some older footage from a video made 5 years ago that most people never got to see. I decided to reediting and added a lot of commentary of what was going on. Elliot Seguin's Youtube channel: https://www.youtube.com/@utopiasnow