I've never seen one just hone in on a swimmer and go straight for him like that. Something about the splashing must have triggered "animal in distress"
I have such an irrational fear of gators. There is a reason they haven't really evolved in a jillion years, they don't have to.
I almost wonder if the drone could have dive bombed the thing and distracted it.
I will say though, I've never just put my face down and swam lap style like that without being able to see around me. I'd kind of like to see more of that clip to see where the gator came from and how long that dude was swimming like that.