Near Death Experiences can have common features, even involving those with little or no religious background (and across time and religious cultures). There must be physiological reasons why a percentage of people experience death in similar ways. Explore in particular a sense of light, as well as the presence of guiding beings. Place special emphasis on psychological and physical models that explain this, and rely upon academic literature. Wikipedia is a good place to start: https://en.wikipedia.org/wiki/Near-death_experience.