Not quite the same thing. You, hypothetically, shoot & kill your friend. Nothing is in dispute.
Alec Baldwin shot and killed Halyna Hutchins. That's neither hypothetical nor in dispute as a fact of the case.
Moreover, in my example, I am not assuming that I would come forward and say "That was my fault!" I merely describe what happened, not whether the person in that example takes responsibility. Indeed, on your view, Baldwin would only have a duty "if he signed a contract" and he admits that he did it.
Here is a fact: If you follow the gun safety rules, people don't get shot. People only die when the rules are broken.
Here is another fact: Baldwin broke these rules. He did not treat the gun as if it was loaded, but rather assumed it was unloaded and failed to do a five-second check which can be performed by a child (literally just turning a cylinder). He put his finger on the trigger when he did not intend to fire. He pointed the gun at something/someone he was not willing to destroy/kill.
Here are some facts more specific to the case: To fire a Colt SAA you have to cock the hammer back and then pull the trigger. The gun requires the operator to perform two steps. Pull the hammer back with your thumb and then depress the trigger. Baldwin completed both of these steps. It didn't just "go off."
Here is another fact: Alec Baldwin was the last person to handle the weapon.
So far as I know not a single person has come forward & assumed the guilt. On the contrary, they all seem to be blaming each other. So to say that Baldwin has a “duty” in these circumstances doesn’t hold water IMO.
Whether or not he had a duty has nothing to do with whether he assumes the guilt. If I kill a family drunk driving, I don't get off the hook by blaming the bartender. Your line of reasoning here doesn't really make any sense.