I can see why Vytas changed his vote, and it probably wasn't that he didn't want to draw rocks. Last week, Culpepper used the excuse that he didn't want John to link up with his wife (if she made it back into the game) at the merge. I can see him thinking, "What if Culpepper decides that it wouldn't be good for him if I partnered with my brother, Aras (another strong player) after the merge?" Culpepper was setting things up as to what was best for him, not the tribe, which wrong at this point of the game. He got rid of a strong player now when the tribe needed him because of what he thinks could happen later, and in the process weakened his own alliance. Apparently Hayden still though he could be trusted, but Vytas decided he wasn't trustworthy.