Harry, whilst very smart with the shield move, I think has missed a vital point - who he wants in the final with him.
I am pretty sure he doesn't want other Traitors to share the pot, but both the others who he recruited could be very difficult to get banished.
And I am sure there will have to be faithfuls. I wouldn't want Jaz, Zach, Evie if I was him as potentially too clever. Or Jasmine as unpredictable. Which only leaves Millie and that's not enough. He should have kept Charlie in...