Firstly, after he decides to leave, he immediately goes and gets Spike, via ripping his cage bars out.
He breaks into the throne room in order to save the main characters.
After Tirac takes to the sky in his chariot and is declaring his victory, Scorpan, instead of just taking Spike and leaving everyone in the lurch, flies up and attacks Tirac directly. He even withstands a hit to the face before Tirac manages to shake him off.
Megan hits Tirac and forces him to drop his Rainbow of Darkness.
From the second TV Special, there's Catrina's redemption.