But why would anyone besides oryx be in his personal dimension and im not sure if it was stated that1 he is unkillable in his dimension 2 all powerful in his dimension 3 is the master and controller of that dimension rather than just an inhabitant of it 4 has a physical body while in it. I got the impression that at the end of the campaign he fled to his dimension because it was a safe location where he knew he could not be followed or that it was a john carter like scenario were he was projecting himself rather than physically in the earth dimension and he was retreats to prevent is projected self from being destroyed as he can be killed while in the earth world as seen during the raid. Which i assume would permanently kill him