I especially don't like the Glock takedown procedure for this reason. To take off the slide for cleaning, you pull down two small pins that protrude from the frame just under the muzzle, then pull the trigger.
What could go wrong? Lots of people cover the muzzle with the palm of their hand as they depress the release pins. When the trigger is pulled, it is pointing at the middle of their hand. I reach up from under the frame, pull down on the pins, point the weapon into a bucket of sand, and pull the trigger. I have had the slide fall off into the bucket. I have never had a round in the Glock, but I still won't cover that muzzle with my hand.
Here's a story from a U.S. Marshal. He got interrupted, left the firearm in an unknown state, came back to it thinking it was unloaded and didn't check. He put his hand over the muzzle to release the slide and pulled the trigger. He got lucky. The round buried itself in his toolbox. Surgery repaired a lot of the damage to his hand.
I think this happened about a decade ago.
The bullet (a Black Talon no less..) shattered my ring finger meta-tarsal, and 'removed' two others. It destroyed the flexor tendon of my ring finger, almost separated my pinky tendon, and exited the right side of my wrist just above my watch band. There was a definite exit hole, but the blast force blew the side of my palm WIDE open about three inches in length. I didn't even see the exit wound until I removed my watch for the FD. Anyway, nine hours of surgery, three screws, a tendon graft from my forearm and about two-hundred sutures later I was put back together.