Using the Mindscape to attack one's mind directly will be quick and simple. But they decided not to use this method against the god of knowledge so that he won't learn new things about them and gain more Leverage of Knowledge over them.
They had many ways to stop him other than using the Mindscape to attack his mind directly, but they let him go because they didn't need to kill him and because they had a better plan for him. Besides, they have more important things to deal with at the moment, so they let the god of knowledge escape for the meantime.
They said to themselves as they gained control of the Crown of Nobility, "Anyway, he can't escape from us anymore."
With their mind made up, they quickly gained control of the Crown of Nobility. Then they took it away to the Mindscape to give it to their true body.
They left the authority of justice behind. This was because they didn't need it. They also didn't have the time and energy to care about it.
