First off prince Hamlet is the son of Queen Gertrude and the recently killed King Hamlet. As soon as prince Hamlet's father died his mother Gertrude married prince Hamlet's uncle also known as king Hamlets brother. This caused prince Hamlet to have a lot of resentment toward his mother and uncle (step father). As soon as prince Hamlet found out thru his father's ghost that his uncle had killed him he decided to revenge his father.
Second of all Hamlet decided to take actions with his own hands because he knew that if he didn't revenge his father no one was going to do it. "That I, the son of dear (father) murdered, prompted to my revenge by heaven and hell. (Act2.sc.2line612-613). The theme I have choosen is very important because it is a topic that is carried from the beggining to the end. Hamlet decides to carry it throughout because he wants to make justice to his father.
Third and lastly of all Hamlet hints his uncle thar he knows something about the murder "This play is the image of a murder done in Vienna". (pg151) This could give the king an idea of what Hamlet might want to do because Hamlet in the play basickly tells his whole plan not only to the king but to all the people that are there.