I think she she is making the best possible use of the HOH. She was in a spot where if she stuck to her plan and put up Brenchel most likely Rachel would go home this week and she isn't nearly the threat Brendon is. And she was almost guaranteed to go home next week if she didn't win veto. By making this deal with Brenchel, she gets to send Brendon home if someone wins the veto and uses it. And if it isn't used, someone on the vets side goes home and she probably will be safe next week. Contrary to popular belief, Brenchel isn't any more likely to break a deal then J/J (who has admitted several times they will put Daniele/Kalia up ASAP despite any deals they might have made) and they really don't owe any loyalty to anyone because everyone wants them out.