Given the marine interests of this of this blog, let me step out of our usual topics and emphasize something that is of important interest to all of us: Drowning does not look like drowning.
Please read this important article explaining that a person who is drowning will not waive his/her hands like we see on TV.
And if you find that article illuminating, then please read this follow up that explains how to save someone who is drowningv without leading to to your death (I remember quite well my Red Cross Lifeguard training instructions to approach a drowning swimmer from underwater and how to avoid the “death grip.” While you must be cautious, there are options available.