I can't believe that Holly voted in Melanie either! Why would she vote on the only person she has competition with for Scott's attention? I personally think Melanie is playing the game. In her attempt to gain trust in the women of PH, she is lying to all of them.
This could go one of two ways.
1) Both Melanie and Holly could go for Scott when it comes to roommate selections time. This would force Scott to choose between the two. Sparks could fly if he doesn't choose wisely.2) Fox could give Melanie immunity from being sent home. In this case, she would probably choose Keith or Dave to ensure that either Charla or Tara will be sent home.
Any other ideas out there?