Concept Of Duality: Slave Trading
The ninth floor was not as joyous and wholesome as one expected. Arthur recalled his words to Aryan, in which he mentioned that opposites existed for everything. Life caused Death, while Creation was a catalyst for Destruction.
Duality was the most prominent feature of the universe.
The ninth floor also had an opposite to its external appearance; a dark side. Slave Trading was the most prominent attraction of the ninth floor, but was meticulously masked by those who conducted it.
Slaves were captured, shipped, and sold on the ninth floor through the vast connections of those who managed the events. Although the act was publicly condemned, not many were of its existence in the first place.
As mentioned, the higher-ups were meticulous in hiding it.
However, those who were aware of it could easily participate in the event, since more visitors equated to higher profits. The trade was not restricted to public figures and more powerful players.