How is Palpatine getting so many “Power of the Darkside” shocks?

I have just experienced the same thing (3 massive shocks in a row!), and could not understand what's happening. But there's no Thrawn even on the AI team, it was Bastila Shan (Fallen), Darth Vader, Boba and Dooku except EP. I was shocked in the game and myself (of such unfair action ?)...