You also have to look at the jury composition..... if they vote off Sabrina, Kim, Chelsea will they vote against any woman in the final 3 vs the guys? If they are bitter about the break in the alliance, they might vote for one of the guys - not all juries vote for the best player..,,,,,
Also, you never know about the challenges. If they are less physical the playing field is even. If it's strength (i.e. holding sandbags on shoulders) the guys have an advantage. Endurance is even.
Also, any of the women could decide to bring Christina to the finals since she doesn't seem likely to get votes from a majority of the jury. They just dislike her. If she 'flips', then they will target her for elimination.
Also, if they flip to the 3 men, they have to get what's his name out at some point to increase their chances at winning immunity - otherwise, he'll likely dominate the challenges and be harder to get out later .