Looks like he's about to blow his foot off... Selector on fire and the barrel right into his foot
Never been in the military, huh?
On the AR-15/M-16 series rifles the sear is built in such a way that you *cannot* engage the safety when the weapon is not charged[1]. That is to say that the selector lever will not go back into safe if the weapon is empty and the bolt is in a forward position with the hammer down (uncocked, uncharged, locked but not loaded, however you want to phrase it.)
While you *can* charge an empty weapon, to get into the configuration where the weapon is on safe and empty in normal operation you'd have to charge the weapon then put it on safe[2]. With an empty magazine, the bolt would be locked to the rear unless you then hit the bolt release, and the dust cover would be open unless you closed it. Without a magazine in the weapon, you could charge it and either manually place a round in the chamber or leave it empty, but you'd still have an open dust cover unless you manually closed it after charging.
While firearms safety tells us to always treat a weapon as if it's loaded and to always safe a loaded weapon, in a battle rifle being able to quickly know the status of your weapon is arguably significantly more important than minor firearms safety practices.
In the M-16, the U.S. Army went overboard in status- which is why unlike an AK-47 the bolt will hold open when you run out of ammunition- which has given enemies in past conflicts an indication of when to attack a soldier who's reloading. The counter-argument is that the soldier doesn't spend time pulling the trigger on an empty chamber if they've lost count of their shots and reloads are quicker and it's easier to maintain an offensive position with since you do not have to re-charge the weapon when you reload, just hit the bolt release with your thumb after inserting a new magazine and squeeze the trigger.
So, with the M-16 series, you're always in a firing mode unless you have a loaded weapon, in which case you can place it on safe.
It's an individual weapon, so you get yours, and yours is your responsibility and it shouldn't be out of your hands unless stacked or racked somewhere and since you get to memorize the serial number and you don't mess with anyone else's weapon you should always know the status of your weapon and every time you load it when you're not engaging a target you safe it.
If you're dumb enough to load and charge the weapon, then put the dust cover back up over the bolt and point it at your foot without putting it on safe- well I sure wouldn't want you in the next fighting position over- so shooting yourself in the foot is good for you and good for your fellow soldiers, but it's not easy to do accidentally
.
Paul
[1] Generally speaking other than testing operation after reassembling the weapon from a field stripping/cleaning the only time you charge it is when it's loaded, so there's no ambiguity and the intent is that you can only safe a loaded weapon, however it's accurate that you can charge an empty weapon.
[2] It may technically be possible to safe a weapon where you pull out the rear swivel pin, "shotgun" the upper reciever, reach into the trigger group hosing and manually cock the hammer then close it back up- but I haven't tried that.