When you arrive at Malachor you're almost act something like HK-47 is supposed to act (a a mad robot on a search and destroy mission). Nothing is said, and you just make a mad dash to wherever, which eventually turns out to be the Trayus Core.
I'd've love to have seen Atton/Sion fight, especially since I don't have Atton as a Jedi (because I don't want him to be, I like him more without the Force than with it)