Recruitment For A Cause.

Even if he did unseal them to fight them, the first experience of the relentless pursuit of a ghoul as taught him the lesson not to mess with them. He can lead a single ghoul around but doing that with a million of them sounds like a good way to court unnecessary death. 

He took one last look at Rinoz before leaving resentfully. "This Rinoz will get what's coming for her. She managed to take the fun out of the ghouls."

He doesn't regret unsealing the ghouls since they served their purpose well. But he doesn't like that Rinoz has commandeered them away from the purpose he had for them. He unsealed them to create chaos and death in the plane but Rinoz is robbing him of his fun. 

The other clones tried to encourage him. 

"At least we now know why the Rinoz was thanking you when you were about to unseal the ghouls. Knowledge is always welcomed."

"We also know what fate awaits pawns. We must never become the pawn of anyone."