I assumed they all had to vote for Carter not knowing for sure if Abi had another idol or if she was bluffing. If she had, whoever's name she had down would have gone. I know she voted for Carter, but if she had had an idol and put down any one else's name, they would be gone. I'm sure they just didn't want to take that chance.
Lisa and Skupin would be wise to make a deal with Abi and vote off Denise if she doesn't get immunity next week. They can't vote Malcolm because he will play his idol. This is their only chance to make a move.
I actually think Lisa could win if things fall the right way and she makes the right moves.