All doomsday scenarios are just plays on man's greatest fear, the fear of death. As a matter of fact almost all fears are offshoots of the fear of death. I mean death happens only once so what does it matter if it is in a zombie apocolypse, war or some sudden collision with some space matter or you just pass on during your sleep. I welcome death, it holds no fear for me. I still try desperately to avoid unnecessary pain and suffering, but that is another matter.