The life guard left the beach unprotected to save another he should have been fired and the person who was saved should be sued for damages
No, he did not leave it unprotected.
Company officials said other lifeguards watched over Lopez's area during the rescue and were on the phone with 911 operators.
"The beach remained protected at all times," Ellis said.
He was fired, that was actually the point of the article that you didn't bother to read. Also it's in the thread title. No one is disputing the legal and/or contractual obligations involved in terms of what he should or shouldn't have done.
What it really boils down to is the moral and ethical standpoint. Which I assume must be a foreign concept since you think they should be suing a man who almost lost his life for something that could have, but did not happen, and in fact wouldn't have happened as the beach was not left unattended at all.