Following Darth Maul’s laying out of plans to take over Mandalore (and Darth Maul and Pre Vizsla both trying to put the other away following the attack), the plan is put into action and executed perfectly, allowing Pre Vizsla to take over power from the Duchess of Mandalore to be the new prime minister. Shortly thereafter, Darth Maul approaches Pre Vizsla to discuss next steps:
Pre Vizsla: “The transition of power will be seamless. We now have the support of the people and Satine to bait Kenobi. With his demise, our deal will be complete.
Darth Maul: “Your oversight requires correction. We now have a base, an army, and the means to expand to other neutral systems.”
Pre Vizsla: “It wasn’t an oversight. It was intentional. I don’t have an interest in the other systems.”
However, Pre Vizsla does not have the same grand plans as Darth Maul does, which makes sense, since he has, all along only desired control of Mandalore.
Pre Vizsla then tells Darth Maul, from whom he is sick of taking orders, “Your vision no longer matters.” He has him promptly arrested (seemingly having arranged to do so with other Death Watch members previously). He then finishes off by saying, “Oh, don’t fret. I’ll still honor our deal. Kenobi will be dealt with. But now you’ll do as I say.” Clearly, Pre Vizsla is very much enjoying having the upper hand in their dealings, as well as having achieved what he wanted – control of Mandalore.
Pre Vizsla then takes Darth Maul out to the waiting masses and announces, “The violence is over! The last of the parasites infecting Mandalore has been caught,” referring to Darth Maul. “The Duchess has abandoned her duty to protect Mandalore. Her political dream only encourages aggression against our planet. We have learned from this beast the consequences of pacifist principles. It’s now time to restore the traditions of Mandalore. No one will ever threaten us again!”
Darth Maul is then imprisoned alongside his brother, Savage Oppress.