What if the robber runs away and chases and cuts him?

If you cut him in the robbery, it's self-defense. If you run away and chase him directly, it's excessive defense or negligent injury and intentional injury.

Those who constitute the crime of intentional injury will bear criminal responsibility, but there are circumstances of lighter punishment when sentencing; If it does not constitute a crime, it shall bear the corresponding civil liability for compensation. Because the other party's fault is prior or there are triggering factors, the civil liability for compensation can be reduced or exempted.