She said so herself, "I am going to stick in my main alliance to the end, I feel that is the best way to win" . This is paraphrased a bit, but you still get the idea.We now know since Ethan , Tom and Kim voted Brandon and Lex did not, that Kim is with Ethan and not lex.
I LOVED the smirk on Teresas face at tribal counsel when Lex told Jeff "my gut is never wrong".
"What a twisted web we weave when at first we practice to deceive"