Regan urges her husband to crush Gloucester’s other eye when one of the soldiers
(designated as First Servant) requests them to stop. The First Servant symbolizes the limits of loyalty. Although this soldier had always been loyal to Cornwall and his wife, he feels that he cannot remain loyal in the face of such cruelty and such unfair treatment of the old Earl of Gloucester. Shakespeare is suggesting that no man should remain loyal to a master who acts in a dishonorable or evil way. Goodness and honor take precedence over loyalty in such cases.
The still angry Cornwall then engages in a sword fight with the First Servant. Cornwall is badly hurt, but then Regan rushes at the servant with a sword and stabs him in the back. The First Servant then dies.
The merciless Cornwall, although seriously hurt, does not stop in his torture of the old earl. He crushes out Gloucester’s other eye so that the earl will never be able to see again.
Thus, Gloucester, who had been metaphorically blind to the truth, now becomes literally blind as well. Shakespeare cleverly connects the themes of madness and blindness in his plot and subplot. The mad king had also been blind to the truth, and the blind earl also experiences a degree of madness (“I am almost mad myself”: Act III, Scene 5, line 154). Madness has no room for truth.
Regan commands the other two servants, who have been watching in shock and horror, to throw Gloucester out of the gates so that he can blindly find his way to Dover.
After Cornwall and Regan leave, the two servants comment on the cruelty of their masters. They can hardly believe that Cornwall and Regan were capable of such wicked and despicable acts. One of the servants then states that he will find mad Tom (not knowing that Tom is actually Edgar) to lead Gloucester to safety, and the other servant adds that he will fetch some egg whites as an ointment for Gloucester’s eyes and some bandages (flax) to stop the bleeding. Even the two other servants realize that, for the sake of humanity, they must disobey their masters.