I tend to agree that there is a selfish component in all human action, but I wonder if it is always to root cause.
There is another possible root cause which in its metaphysics comes back to the same thing,just a broader concept.You were useing someone who risks their life to save another as an example.The late Joseph Campbell use to tell a story about some canyon where he was living being used both for a lovers lane and as a place where people went to committed sucided.Apparently some young man was about ready to jump when a police officer grabed a hold of him and just about went over with him but for a second cop who hauled them both back.Afterward,the policemen was asked why didn't you let go,you were going over with him? His reply was,if I had let that young man go I would not have been able to live another day of my life-----big stuff!
Schopenhaur's explaination is,this is a realization,not a concept,suddenly this realization just grabs you,you and the other are one.The vail of maya has fallen away---or in other words the illusion of time and space which creates separateness,for that brief time is broken and you are the young man about to jump.Actually there is new evidence which would support Schopenhaurs view on this,it comes from neurology,they have discovered what they call mirror neurons,if you are poked at,these neurons fire[are activated] but if you witness another being poked at, they also fire--this is showing us the source of our own morality is humanity itself,bringing self and other together.So,my point in the brief period of which we spoke self and other are one,so in a strange kind of way,it is still selfish,the self now incompasses both.
Outside of the above I cannot think of one acception to this universal rule,all action is at first selfish.Even if you are decieved,you cannot be decieved if you did not think the action was going to serve you in some way,only then would you act.
Perhaps you would like to try your hand at defineing self,self-interest and other ect.. I have a pretty clear idea of what they mean to me,but I am easy! I think it was Voltaire who said,if you wish to debate with me,define your terms------------time for my meds!
Chad,I read that years ago,that is what inspired this thread,thanks for the link.