After what happened, Aren basically removed himself from the tournament, completely forfeiting it. He let the others compete, but as for him, he wasn't interested in it anymore.
In the beginning, when they had all started the trials, he remembered telling himself that he would never feel bad over killing someone, because it was definitely for his survival, but now that he did kill someone when it wasn't for his survival, he wasn't sure how to feel about that specific one.
He could easily blame Loki forever and say it was because of what Loki did, but that was all a lie. The real reason was because he was weak. If he wasn't weak, he wouldn't have fallen into the illusion and taken someone's life.
Aren decided to leave the tower after he forfeited, now no one could tell him anything, after all, this was no longer something controlled by the wargod city, but the system.
