They were setting up a scene, practicing the angles and: "...Baldwin was explaining how he was going to draw his revolver from its holster and where his arm should be for the shot, the firearm went off...."
No, it didn't just go off. Baldwin pulled the trigger. And, since it was just a set-up and not during actual filming, Baldwin should not have pulled the trigger.
"...Souza said three people were handling the gun for the scene."
Chain of custody violation. Only the armorer and the actor should have touched the weapon. We already know they were target shooting (jerking around) with the gun in the preceding days.
"Souza....was not sure if the gun was checked again when everyone returned from lunch."
Again, incompetence and neglect.
Baldwin pulled the trigger when he should not have. His liability. Baldwin was the producer who had control over crew, and they hired incompetent crew. Baldwin's liability. Baldwin was aware of the previous negligent discharges and failed to control the crew HE hired. Baldwins liability.
