I was using my dremel to add a sling to my longshot about 10 minutes ago. I had one of those circular cutting discs on, and right when I touched it to the plastic, the disc shattered and flew away before embedding itself in a wall.

First of all, I was scared to death. I almost lost an eye, finger, hair, etc. That thing went an inch past my face. My hands are shaking while I'm typing, so I'm glad I can spellcheck this. Almost the entire disc was broken except for a small shard which continued to spin creating a cool invisible dremel tool look. That was about where the coolness ended. This has never happened to me in all of my 4 week's experience with a dremel. The bit was secured to its little holder thing with a small flathead screw. I've used these bits before and this has never happened. Why? I'm probably not going to use my dremel before this board is destroyed and everyone is dead. Please help!