She really isn't, if Dave used his points wisely you wouldn't waste one point revealing where the person was on the ladder, you would give them a point automatically to see where they are (like Priya did). Once he saw this, he would've noticed Priya and Skye both on low points and easily could've said 7 points to Skye and 4 points to Priya, ensuring Skye was nominated and pushing Priya further up the ladder. Except he wasted was it, 3 points? on revealing where everyone was. Priya is the ONLY one to see through this and just give a point and you'll reveal where they are anyway.
Educate yourself