Kristen thinks that if Rachel was on the block with someone else, Rachel won the Veto, and Brendon goes up, Rachel could go into game mode to keep him.
Rachel says what if she couldn't get the votes against who he was sitting with?
Kristen what if's with Kathy/Rachel on the block.
Kristen says that Rachel/Brendon are the strongest alliance in the house (what the hell?).
Rachel says the house wouldn't keep Brendon/herself in there.