Which protocols did Baldwin break? The scene in question requires the actor to raise their gun and cock the gun so it can be seen by the audience, now presumably the director wanted an angle where the actor is pointing the gun towards the camera, which isn't uncommon. We've seen this kind of shot in movies a hundred different times. There's nothing crazy that happened it's not like Baldwin strolled onto set and started doing stuff that was way off script, he was rehearsing the scene exactly how it was written in the script and they were lining up the shooting angle exactly how the director and camera woman wanted the shot.
There's not supposed to be a f***ing real bullet in the gun, never, ever, never, ever, ever, ever, ever, EVER. lol, that's the problem and that is the fault of armorer not doing their freaking job.
Even if the assistant director screwed up (which he did) and called it a cold gun (which he apparently did) it should never result in someone getting killed because the worst thing that should happen is the actor accidentally fires and all they fire is a blank, and a blank should never kill anyone. That's the *whole* point of blanks, lol. Even an accidental discharge should never result in a death on a movie set. Although in this case I believe it was supposed to be a dummy bullet full stop, a dummy bullet isn't supposed to even fire, it's only there to show the audience that a gun is "loaded" but it can't fire. So a dummy bullet is even more idiot proof than a blank.
If I hire you to be an extra on a movie shoot and I hand you a sword and tell you it's safe and then tell you to swing it at a group of zombies and on the second take, the blade flies off and impales somebody, is that your fault? Somebody f***ed up by not checking the integrity of the sword. That should never be the job of the actor, it shouldn't frankly even be the job of the assistant director or director. The prop master/armorer should know every damn weapon on set and have inspected them forwards and backwards before they ever get within 50 feet of a performer.