The way safety works is you want multiple layers so if one fails (armorer puts out weapon with live rounds by mistake) then the weapon is checked (by AD before handing to actor) and the weapon is STILL treated as "hot" by the actor and they don't point it at anything important (like people) without even more safety checks (like a barrier, remote camera, additional weapon checks, specific safe zone to discharge weapon, etc).
So it's quite possible Alec did all he reasonably could as an actor. But he might have been able to do more, and as his role as Co-producer perhaps a LOT more.