She was a crafty enemy, and conventional methods wouldn't work on her.
If I told Sasha and Michael now that I'd said so many bad things about Joanna to them, they wouldn't believe me.
I didn't have a recording of my conversation with Joanna, and even if I could repeat what Joanna said, I didn't have any proof.
Maybe I didn't have to make a complicated plan. I didn't have to prove to Michael that Joanna was a bad person. I only had to find a way to make Joanna lose control in front of everyone. Her previous disguises would fall apart if she took off her mask.
But how could I make Joanna lose control?
She didn't believe Michael would mark me so I would show her.
I'd get Michael to mark me and show it to everyone so my connection with Michael would strengthen, and Joanna would have no reason to stay here.