Death, it's an odd thing, but I have a theory on it, it involves the concept of parallel universes also.
What I beleive is, when you die your conciousness switches to a parallel universe where your death never occurred, without your knowledge or any recollection of your death, just the events right before it.
For example, somebody gets shot. He dies, quite obviously, his conciousness switches instantly, to a parallel universe where something happens and he doesn't get shot, like a bird flies in the path of the bullet, or the man that shot him has never been born, he has no recollection of his death, only the past that has happened in this new universe, and thinks himself lucky to be alive.
So everytime you've come close to death, such as nearly getting hit by a car crossing the road, you have died, and been moved to this new universe, where you didn't, everybody in the old universe, possibly saw and/or knows you died, but you don't and neither do the people in the new universe.
Food for thought....