The drowner was panicking, and tried to climb up this other guy.
He had to punch the guy in the face as hard as he could to get away from him.
Yup it happens
During life saving training you practice all sorts of scenarios so you can get some experience with them
I was at a water park. There was a slide that came down into a clear tank of water maybe 6 feet deep. A brother and sister, about 8 and 10 go down the slide together. They have these little life jackets on. Brother panics when he hits the tank. Grabs his sister. The teenage lifeguard realizes what’s going on. They almost drowned him both trying to climb him. Scary. He finally got one on the deck, then the other. Just scary and so quick.