If my memory serves me correctly, it said in the article that his friend was cleaning off the back of the boat and didn't see him hit his head and fall in. The friend said that he thought that Saban was joking and that if he went over there then Saban would come up and grab him.
All I read was what was posted here. Based on the first post in this thread, my initial thoughts were with friends like these who needs enemies!! I could envision Houston Nutt or Phil Fulmer being the other guy in the story. Still, 30-50 seconds is a long time to wait for someone to reach up and pull you in with them.