A Large Chain Store manager threatens to fire employee if employee leaves office. Is it leagal ?

Employee has problem with manager and wants to know how to handle situation and meets with store manager. Store manager turns it around and talks over employee and won't listen and says he doesn't hear a problem. When employee can see he is wasting his time, he is going to leave and store manager demands he sit down and he's being subordinate and if he goes out door he's fired. Employee is being treated as if he was in school instead of at a job. Being treated as though he has no rights to walk out the door. Employee hasn't ever raised voice or said anything other then refusing to tell all the things manager has said or done to employee to avoid risk of additional trouble from whom employee is already having bullying harrassment from. Especially since store manager doesn't want to acknowledge it and is protecting the other manager.