Obsession and Madness Abyss puzzle walkthrough in Crimson Desert

The Obsession and Madness Abyss puzzle in Crimson Desert is a strange one. Firstly, because it's actually called the Sanctorum of Insight — though you won't know that until you complete the "Obsession and Madness" quest. Secondly, because there's a secret way to skip the puzzle and immediately restore the Abyss. And thirdly, because an unfriendly fellow may thwart your plans for abyss exploration.