Disclaimer: I don't own Star Wars or The Clone Wars.
Spoilers: For Episode 16 "The Hidden Enemy"
Slick
He's sitting in a prison cell, hands cuffed and waiting for his trial and probably execution (he has no illusions about wartime justice), when he realizes that he is freer than he's ever been in his life.
He's gone beyond them all—the Jedi, the Separatists, even the Republic itself. He's taken out their weapons, struck a decisive blow, but even if it comes to nothing it won't matter. He's won anyway.
They can lock him away, they can even execute him, but they can't make him obey. He's broken their rules, disobeyed their orders, defied his creators and their programming, and nothing can take that away from him.
His brothers come with food and questions, and when they're actually willing to listen (which is sadly rare, but he understands), he tries to tell them why.
Once Rex asks him mockingly if it was worth it. He's expecting anger or defiance, and Slick can see that his calmness unnerves his former commander, just a little.
But it was. Even if they kill him it was worth it.
He knows now that he is free. They can never make him obey.