The finality of death when one makes peace with it, no longer is a fear factor.
When faced with a deadly situation our instinct like that of all creatures, is to survive. When we are suffocating we gasp because our physiology demands oxygen in order to survive and we are aware that if we can't breathe we'll die, so we fight tooth and nail to breathe. All creatures behave the same way - it's Instinctive. Humans though fear death on a much vaster scale because we obsess over our mortality. Let go of that obsession and the need to survive remains but the fear of death fades away.