During the three months of Yi Yun's growth, the door connecting the Divine Perish Hall to the ancient battlefield vanished. Now, it was impossible to leave the Divine Perish Hall as it was completely isolated from the outside world. The warriors that entered appeared to be stranded in a deserted island amid the vast seas, unsure of their future.
And such complete isolation, with the possibility of being killed by the environment at any moment, easily triggered the darkness deep in the human psyche. Of the thousands of warriors that perished in those three months, at least a third of them died at the hands of other warriors and not from the Divine Perish Hall's dangers.
It was easy to discover acts of murder and plundering in the Sinkhole. If the faction backing the victim pursued the matter, the perpetrator would usually be struck with swift revenge.