The time of death is a crucial moment for the human being, because this is when his next destination is determined. This is the moment when he has the opportunity to go back to Godhead. Everything in a devotee's life is leading up to this point, is a preparation for this one major exam. As it is said, "Whatever we do in life will be tested at the time of death."
The atheist and the devotee each perceive death differently, just as a kitten and a mouse each perceive the jaws of a mother cat differently.
The jaws of a mother cat represent shelter to the kitten, but they represent a horrible end to the mouse. Similarly, when Krishna comes in the form of death, it is the ultimate defeat to the atheist, but the devotee accepts it as Krishna coming to take him back.