Upon reflection, this might actually have been a decent move. Karishma might not have been any kind of challenge threat, but she was at least showing some fire in the last couple of episodes. Again, I feel like there was some edit trickery because it should not have been this hard to vote her out at any point in time. And if she was truly that weak, they should be dragging her, by hook or by crook, to that Final Tribal Council, because you are effectively increasing your odds or winning.
Dean seems to think that his 3-person alliance is strong despite every indication that Lauren and Tommy are a power couple of sorts. Noura is seemingly both aware and unaware that she is #5 in a 4 person alliance. And so if that core four is not targeting Elaine next, I'm not sure what they're doing.