Suppose you have a bodyguard who sees someone is about to attack you. The attacker is not being a threat to the bodyguard but a dangerous threat to the bodyguard's employer (he could be killed) . Can the bodyguard act harming the attacker to prevent him from killing someone, even if he isnt the one who is being personally attacked or he will be punished if he does?
So-called "self-defense" laws are not limited to just yourself. For example in Washington, RCW 9A.16.110
No person in the state shall be placed in legal jeopardy of any kind whatsoever for protecting by any reasonable means necessary, himself or herself, his or her family, or his or her real or personal property, or for coming to the aid of another who is in imminent danger of or the victim of assault, robbery, kidnapping, arson, burglary, rape, murder, or any other violent crime as defined in RCW 9.94A.030.