In the event of a body's catastrophic system failure (i.e. serious injury / dying) the brain spikes the endorphin levels since pain no longer serves a useful pu

In the event of a body's catastrophic system failure (i.e. serious injury / dying) the brain spikes the endorphin levels since pain no longer serves a useful purpose: the damage is done but it does serve a useful purpose to reduce the pain levels to allow us to function at a higher level than writhing on the ground in agony so that in some circumstances we might live to see another day. Think of it this way: a bear just ripped/slashed/whatever your arm off... which is more useful: 'arrgggghhh!' or for the brain to pump out endorphins so that you at least concentrate and have a chance of fighting back or running/limping away or hiding? I doubt the brain differentiates between serious injury and dying, it's just wired at a certain point to try to minimize the pain. That would seem to be a very useful evolutionary purpose.