Originally Posted by FireWalker
good question... the LN tells you why. I'll avoid saying more. Just say it's really not hard to figure out.
Think about it this way. 2 "good" aligned guilds come into conflict about who gets to fight a monster in a literal death-game. How might they solve this problem without killing eachother?
Work that riddle out or read the LN (2nd book i think).
As to this episode... That scene was uncomfortable to watch... and that was one of the most literal cases of dues ex machina I've seen. That said, it works.