let me say why:
If you vote Katie, regardless of how we vote, the best case scenario is Riley firemaking which she wins, and the worst case scenario is that she gets immunity and makes it to the end. Keeping me places a hedge bet against Riley to win the immunity, but does not guarantee we can send Riley out.
If you vote me, you lose that hedge bet. Riley IS the strongest challenge player behind me, you just saw it happen. Your chances of taking away the immunity fall away drastically.
Voting Mike both keeps your hedge bet AND makes it possible to 3-1 her at tribal.