The eagerly anticipated merge occurred, and Murlonio ("from the sea, united" - good grief) was formed. No one seemed to figure out that perhaps "Marunidos" might have been a little more plausible. Matt had won the immunity challenge that mattered most, and now we had a distribution of five former Zapatera and seven former Ometepe - or should we say six former Ometepe and Matt?
I suppose it was too early for Phillip to flip. They had the majority, but only just. With his Samurai philosophy he was going to be honourable for the time being. It looks like they had to forget the past and ensure that they were now all on the same side for the sake of survival. After all it would have been rather silly for the ex-Ometepe to get themselves all voted out one by one when they could get rid of Zapatera first. And he might have figured out that by flipping, he would have traded his weak position in one group for similar status in the other.
Matt was now all alone in the world. He did managed to start a special interest group in religious discussions, and Rob was concerned, not because he was against religion, but because these people with a common interest would likely take the common action of voting together. Steve realised that Matt had the need to join forces with someone, and if he could get both Matt and Andrea on his side, they could achieve great things. So Matt could choose with side to take, and was the vital swing vote.
In such a situation, he was a little too honest with Rob, and admitted he had considered flipping but due to his faith he would not. Unfortunately, Rob must have listened selectively to him, and only heard the words "... vote you out ...". This triggered off an impulsive reaction from him, and he instructed the rest of his alliance to vote for Matt.
It seems that no one really likes outsiders. It's fine if there is one main alliance and someone doesn't belong to it - clearly that person must go. But if there are two alliances and someone is somehow torn between them, the tendency is to think that this person cannot be trusted and must become the target. Surely it would have been better to vote out one of the ex-Zapatera rather than Matt, but they could have told him to vote for someone other than their real target, just in case he was disloyal.
The thinking in Zapatera was that Ometepe saw Mike as the biggest threat (he was runner-up in the challenge) and would have been keen to get rid of him first. If they could get Matt and Andrea to join them, they would have the majority and could vote out Grant - who looked too strong for their liking. At tribal council, Ralph played the idol to protect Mike, but Ometepe had probably thought it too likely that they would have protected him, and had already made up their minds anyway to vote for someone who they would never have bothered protecting. Matt pondered for a long time about his vote and eventually voted rather tamely for Steve. He was blindsided once again, and received all six of his ex-tribe's votes, while Grant got all five ex-Zapatera votes. No problem, he had a return to his Redemption Island spiritual home to look forward to.
With Matt gone, the tally reads six ex-Ometepe against five ex-Zapatera. Add Rob's hidden immunity idol to the six and ignore the idol that Ralph wasted on protecting Mike, and it should be comfortable for Rob and company for a while. Apparently Phillip has been faithful so far, perhaps waiting for his side to have an even bigger majority before doing anything just yet. However, we are told in next week's preview that Grant wanted to "be his own man". If this means he deserted to the enemies for protection (given that they targetted him) it would have made the game more exciting but may not have been the right move for him.