When you come to the part where Robin has gone to see Poison Ivy to get kissed, he gets pushed into the pool in front of her chair. Later on he trys to come out of the water to get a breath. If you look carefully, you will see that when he comes up out of the water, he doesn't go back down on his own...the tape of him coming out of the water gets rewound and we see that! Maybe they lacked good enough footage. Maybe...