Casu wasn't worried about anything in there. No fights could erupt due to the laws, after all. Not at his level of cultivation, at least. Now that he was in front of the Path of Reincarnation's entrance, all he had to do was release the souls he captured, and they would enter the Path of Reincarnation on their own.
However, everyone back in the Meeting Hall was closely watching the scene unfold. None of them could warn Casu that the twins were there even if they wanted to. Of course, it wasn't that they couldn't, but that it was part of the Elder Devils' agreement. Each Elder Devil had a close eye on every participant to prevent them from being helped by their elders outside. In any case, they wanted to see what the twins and Titia were planning.