The rank of relative absolute refers to the absolute state, where you experience the great death, explode, see the Way, and penetrate the noumenon. When genuine practitioners have built up accomplishment at inner seeking and are filled with the power of hidden cultivation, if they suddenly break through, then space itself vanishes and iron mountains shatter. Above, there is not a single tile to cover your head; below, there is not an inch of earth to stand upon. There is neither affliction nor enlightenment, no samsara or nirvana. It is totally empty and still, with no sound, no scent, like a bottomless clear pool, like trackless space.
It often happens that people take this rank to be the end of the whole matter; considering it attainment of Buddhahood, they cling to it obsessively, never letting go. This is called Zen in stagnant water, where one becomes a ghost haunting a corpse in a coffin.
Zen Master Hakuin in Kensho: The Heart of Zen, pages 72-73