Yeah I think thats right.
Kitana knew the truth about her past and was trying to bring down Shao Kahn's reign from the inside by liasing with Liu Kang (although it was stated that she helping the 'Earthrealm warriors' it seems more likely that it was direct with Liu Kang), but she didn't let anyone know she knew, including Jade who was oblivious to the truth about Edenia.
Mileena found out about Kitana and the 'Earthrealm warriors' being in cahoots, Kitana killed Mileena, Kitana was imprisoned for her treachery but escaped so Shao Kahn sent Reptile and Jade after her.
Does anyone have any further views on this?