Lifeguard fired for having rescued drowning man

He abondoned his post which endangered those he was tasked to protect.
Sacking is the correct outcome.

Where was the guy responsible for the "southern" zone?

The southern zone was unpatrolled and has signs saying swim at your own risk.

What I do find strange is that only one story says he saved a drowning man, all the others say the swimmer was already rescued and on the beach being treated by a nurse by the time Lopez arrived at the scene.