According to Osho, as life energy withdraws it shrinks into a seed at the very center you have lived from—the most active chakra in your life. At death it concentrates and exits through that door (sex center, heart, agya/third eye, or sahasrar/crown), and your next birth resumes from the same center.
When you die, your energy goes back to the spot you used most in life and leaves from there to start again.