I have no dog in this particular fight, but it's worth mentioning that you shouldn't endanger yourself to save someone else. It usually just creates two victims without professional support/equipment.
I don't believe this to be true; is there any evidence? Outside drownings where people can't swim?
People save other people's lives all the time. We hear about it and also would hear about people dying in the attempt and yet.. Don't hear much about it.
Just seemed like a fun thought experiment.