ok think about it like this:
You find yourself in a dark alley and you see one of your good female friends being raped by a sketchy guy, you act out of the urge to protect your friend and stop her from being raped by this despot- You beat the rapist to shit,ultimately killing him. You did that to defend your friend and to do the right thing, if you hadnt intervened you would be left with a guilty conscience for not stopping this horrific act being done to your friend
Okay, now youre driving, youre late for work/date etc and you run a redlight, suddenly a minivan pulls out making a legal turn or what have you, you t bone the minivan(filled with kids) killing everyone onboard. You walk away unscathed, however the people unknown to you that you just rammed are dead. Subconsciounsly you knew that running the red light was an inherrant risk to yourself and others, but did it out of the interest of yourself and others. However running the light was completely unjustified.
In the end, you would find that protecting your friend would be fufilling as you saved her life and did the right thing, but killing a minivan full of people you never knew would torment you for the rest of your life.
I hope i made my previous point a bit more clear, even though these werent the best examples.