Lake Placid - Back in His Mouth
In the beginning of "Lake Placid," the diver guy is tagging beavers. When he is in the nest, he has his mouth piece (where the air for the oxygen tank come out) to his side. But when he is dragged along the surface, if you look real close you can see it's in his mouth. Not only that, but he also sounds like he is screaming like it isn't in his mouth.