Agreed with all points and neglected to mention if you do find yourself saving someone, you did the exact right thing. Communicate with the person you intend to help. Talk to them, tell them you’re here to help and to let you take control. Though this won’t work a lot of the time but still.

As a former lifeguard, I would recommend that no untrained person try to save anyone over 50lbs without a very floaty object. You’ll probably both drown. Even with all my training I’d strongly hesitate to go in after an adult with no flotation device on me. (You’ll read in this article that the girls had a flotation object: smart as shit) They’ll flail and push you right under.

If you decide not to take my advice, keep as much distance from the person as you can and approach from the back, put your arms under theirs and swim backwards with them.