Voting off Rob/Russell should have been first priorioty. They are not in the same class as the "ordinary" contestants/actors and sqew the game, preventing a fair and interesting game to happen because all we wonder is whether they'll vote off Russell/Rob.
The quicker they are voted off and eliminated form redemption island, the quicker the game become interesting between evenly matched contestants/actors.
Rob knows he is pray, so he will concentrate on dividing the tribe and voting off those not part of his clan.
Christine was actually very smart by not playing her idol. She probably voted for the other girl instead of voting for philip. This way, the other girl would be voted off instead of her.