Kenny screwed up big time with his last vote, and it makes no sense. It was smart to ferret out the “idol” by still voting for Corinne, but it made no sense to out himself by voting for Matty. If the idol was real, Matty would go anyway, with 2 votes or 3 votes.
That move by Ken wasn’t even smart. The idol has to be played before the votes are read. Corinne would have had no way of knowing whether there were three or four votes against her.