Going down under is an image of the unconscious where we do the real work of the soul. There in the dark we labor looking for the pearl of great price in order to buy it even if we sell all that we have in order to do so. Jesus used that language to describe the Kingdom of God which is another way speak of the pearl.
The great Saxon poem Beowulf has the same theme. Beowulf travels to the next Kingdom to aid the King in a problem. The great hall of feasting is infested by a monster, Grendel. Beowulf fights and defeats Grendel. Later that night after the celebration a greater horrer erupts: Grendel’s Mother. Following her to the lake of her lair Beowulf courageously dives into the lake and battles the monster’s momma and is victorious.
We must dive in and fight through the issues in the rich darkness in order to gain richness and depth in our souls. It is worth the risk even though we are fearful of the task.