I still don't get why, after the first tie, Ciera didn't just turn around to Gervase and Tyson and say "Look, guys, I'm just really worried about being #4. If you guys really aren't planning to get rid of me at 4, show me now. I'm gonna vote for Monica. You guys should, too. She goes, and it's still us three against Hayden and Katie. But I'll know you guys were honest with me and it'll be smooth now 'til the end."
Right, and Tyson and Gervase are going to trust that. So far, Monica has been 100% reliable and wins challenges. Winning challenges can help keeping an alliance together because they don't have to eat one of their own too soon. If Ciera is telling me she is waffling, no way do I vote with her.
Don't forget that Tyson got knocked off before because he decided to go against a guaranteed vote with Boston Rob. I am pretty sure he isn't going to trust that Ciera wouldn't vote him and then he is gone because it is 3-2-1. Way more chance he gets tricked than he picks the white rock.
Next time during that rocks thing, Tyson should be a little smarter and play the idol. If he plays it before the vote, He and Gervase are safe and by voting Monica, she can't draw rocks and no matter what they can't lose.