This "sinking" was also not a physical descent, just as when Song Shuhang's consciousness had "sublimed" and come into contact with the "Divine Show Saint Rules."
He had originally thought that he would have to "sink" until reaching the foundation of Reincarnation before coming in contact with the "Immortal Information" of the Fifth Heavenly Dao.
But during the process of sinking, Song Shuhang's consciousness was already continuously coming into contact with the data of "Reincarnation + Immortality."
The "passage" through which he sank was infused with the "law and dharma" of the Fifth Heavenly Dao.
The Immortal Information belonging to the Fifth Heavenly Dao kept emerging.
Then... they actively reached out to Song Shuhang, through his consciousness feeding back to his fleshly body on the Su Clan's Ancestor Star, reinforcing his "mental energy."