Interesting points but I'm not sure you can easily correlate survival instinct with selfishness. I suffer from chronic depression, but I also have strong survival instincts. I don't feel bad about being alive just because other people have died, as such. Indeed, death bothers me less than ongoing suffering: I was surprised to note that while I feel a bit sad for the people who died the other day in Las Vegas, and very sad for their grieving relatives, I am much more troubled by the ~500 people who were wounded - they're 'lucky' insofar as they're alive and not dead, but the wounds they suffered are likely to impact them for a lifetime, the more so for being unexpected (vs. the sort of trauma you see coming or volunteer and prepare for, as military people do).