Your boss has come to you and explained that he has just finished a performance evaluation meeting with an employee, Fred. Fred became very upset during the meeting and at the end of it he got up and shouted: "Okay, if that's the way you feel about me, I quit!" Your boss is delighted with the resignation because Fred has been a difficult employee ever since he was hired three years ago. You are asked to look for a new employee to replace Fred. What advice would you give your boss with respect to the legal issues surrounding these circumstances?

This is for Employment and Human Rights Law in Canada. Could you please elaborate and maybe use a reference?