Leave Or Evolve.

He also assumed that since a threat was coming to him, she wanted to achieve two things at the same time by preserving him and getting him to owe her but she had made a hasty plan full of holes to achieve it. 

He was right about almost all of the assumptions except the one where she made a hasty plan full of holes about it. He didn't have enough information, so he made incorrect assumptions and fell into her ambush. She told him about the attack before it happened so that he would fall into her ambush and be pincered.

It worked on Aeternus the second time. She did something and he assumed that she killed all her subordinates to stop him from getting to them. It was a faulty assumption because she didn't kill all her subordinates and she did it to stop him from getting to one of her subordinates.