First of all, they didn't turn on them. Burnie is the one who got snarky with T&K for trying to avoid helping other teams. Hello. It's final four. When you're trying to get into the finale, helping other teams is just plain stupid. They have all been friendly and courteous all season. Now is the time to get serious and stop helping each other.
Second, I don't blame T&K even if they did have an attitude with Burnie because Burnie has been throwing them under the bus since last episode. Burnie basically called them shady for getting Brodie and Kurt eliminated, which is SUCH bullcrap. Brodie and Kurt could have possibly survived after doing their u-turn if it hadn't been for BURNIE using the second u-turn! It was actually brilliant gameplay on Burnie's part... but don't sit there and blame Tyler and Korey for being shady when the ENTIRE reason the frisbee boys got eliminated is because of Burnie and Ashley.