I have something similar. I have KK - flop is KA3. Nice - player 1 raises 8xBB, player 2 calls, I call. Turn is another 3 - player 1 pushes, but it's less than half pot size, player 2 calls and I call. River is an ace, and the player 2 goes all in, which covers me.

THIS IS THE EASIEST FOLD EVER. But of course I didn't even think about it - I had a boat, kings full of aces!

(I came third, btw - beaten by the inevitable Aces full of 3s, and the slightly less inevitable quad 3s)