I had a similar situation occur... It took about two days for the ringing in my ears to stop. I will NEVER make the same mistake again. It honestly put the fear of God into me!
My ND also happened with a Glock (G23). I was pre-occupied with the TV while disassembling my gun. The trigger was already in the "fired" position as I proceeded to push the slide forward and off. It got stuck about half way. I first thought that it had come off the rail, so I forced it back into the original position.
Well... the reason it got stuck had nothing to do with the rail. The loaded magazine in the gun was the actual problem. As I kept most of my focus on the TV I jammed the slide back which then chambered a round. I then pulled the trigger and recieved one of the biggest suprises of my life! Luckily the JHP round fired harmlessly into a bookshelf where it lost most of its energy. I think I was in shock for the next 30 min. It makes me shutter everytime I think about it, but I wont be forgetting it anytime soon!
The fact that it was a Glock had nothing to do with it. Any other gun being taken down would have had the safety off. It was my own stupidity that led to the accident. Lesson learned