Picking up some slack
Idiots. If you're going to test body armor, set it up on a lumber crosstree. Suppose that the shooter had jerked the trigger or missed (even at close ranges I've seen people fuck up the simple.) Instead of one idiot wincing and one laughing, you'd have one idiot on a slab and another in the pokey for negligent homicide.
There are four cardinal firearms safety rules. They do not encompass all aspects of weapons safety, nor do they factor in simple common sense, which both of these tards lacked. Usually Xavier posts these with a disclaimer that his Idiots with Guns posts "...are not to humiliate, but to educate..." I say bollocks to that. Maybe it's the Jarhead in me. People who handle firearms without learning the basic safety rules, or obeying them when they know them, deserve to be held up to ridicule and scorn, because they put lives at risk with their careless behavior.
1. All weapons are loaded. This means you handle any firearm as if it is loaded. Keep the muzzle up, open the action to ensure the chamber is clear, and keep the safety engaged. It also means don't point your weapon at your idiot drinking buddy whom you conned into donning body armor.
2. Never point a weapon at anything you don't intend to shoot. Muzzle awareness. Always ensure you keep your weapon pointed in a safe direction. No goofing around, pointing a gun at a camera to pose for a picture, dry-firing at your buddies (or anyone else,) and no "Taxi Driver" bullshit in front of your bathroom mirror.
3. Keep your finger straight and off the trigger until you are ready to fire. If you have been a dumbass and not obeyed the first two rules, this one rule may be your saving grace. Almost all accidental discharges result from someone stumbling while holding a gun, holstering, or unholstering, with a finger on the trigger. See this, from the same idiots:
4. Be sure of your target and what is behind it. Most rifle and pistol rounds will eat through indoor and even some outdoor walls before coming to a stop, to say nothing of a body. When at the range, make sure there's nothing behind a target (except for a nice, high berm or a pile of sandbags) before firing. If confronted with a threat in your home, pray that some part of your hindbrain assesses the risk before you fire.