Does responder superoir mean that you are fully protected from a law suit?

No. Respondeat Superior is a legal doctrine that allows a business to be held responsible for the actions of the employee. But the employee is still liable.

Example: I'm driving and get into a car crash with a Pepsi truck. If the truck driver caused the accident, he could be held liable to pay for my vehicle or medical expenses. However, if he was delivering Pepsi on the job, Pepsi may also be held liable. Both the driver and the company would be jointly liable.