Why does Vajrayana place great emphasis on the practice of dream yoga? The reason is that, unlike the absolute quietness of death, when we are in deep sleep, even though alaya consciousness and self-grasping are still operating, all other consciousness have stopped. It is much easier to realize the nature of mind when undertaking practice during this period.

~ Depicted from THE HANDBOOK FOR LIFE'S JOURNEY : On Death & Rebirth - Understanding Death