He had betrayed the Fatui, he knew that, but he had his own goals outside of the Fatui. He only longed to be strong and live up to Ei’s expectations, to be strong enough to wield the gnosis, carry out his original purpose. He joined the Fatui to become stronger, gain experience, he didn’t respect the Tsaritsa or any harbingers. Once the Fatui had captured him, after he had been exposed as a traitor, he had to be fought by various recruits until bound to a chair and possible tortured by you.