Quite a number of years ago I had a case head rupture with some ammo which had the case head drawn just a little too thin, this according to the manufacturer. As Graybeard noted, you are very apt to get some gas and brass back in your face if this happens. Well, it made for a trip to the emergency room, and they picked the particles out of my eye, a real sweaty palm experience, for sure. I was wearing glasses, but was looking over them at the time as I was shooting uphill.
The brass had been flowing back into the firing pin opening, making the rifle difficult to open, and I should have stopped when I was ahead. This was a .22MRF, by the way.
No permanent damage was done, fortunately. Much like a corneal abrasion from a hard contact lens. It is not an experience I want to repeat, believe me. I almost dropped the rifle when it happened.
Jack