The biggest exam of Life is death

In Bhagvat Gita Lord Shree Krishna said that the most important moment is what are you thinking about during the process of death because it determines which species you'll take birth next, and it's said that the pain experienced during death is equivalent to 20 thousand bites of scorpion. So what a person really feels during death according to scientific studies? does it anyway related to the chanting of Hare krishna maha mantra? Let's discuss about this topic.