The end is NEAR!

In act 4 of Hamlet right now Hamlet and Claudius are trying to kill each other. I do not understand why their desire to kill each other is the only thing on their mind. It is obvious and ambiguous at the same time. With Hamlet wanting to exact revenge on his father, but also wanting to find a purpose in life, and with Claudius wanting total power over the country and wanting to just continue his manipulative ways, it is difficult to determine which one of their reasons outweighs the other. I find this interesting that each killer is killing for one sole purpose: to kill the other before they get killed, or in the cliche form kill or be killed. This act is purposeful to the end act because it sets up a way for Claudius and Laertes to kill Hamlet. It also gives the reader or watcher the chance to see Hamlet when he finally broke down and decided that killing is the only way to kill and live. On the other hand Claudius and Laertes decide that to kill Hamlet they will have him duel Laertes. Laertes will also have a poisoned blade, and then they will give Hamlet a glass of poison to be sure that he dies. At the end of Act 4 Gertrude rushes into the room and tells Laertes and Claudius that Ophelia has drowned. They are both shocked, and that is the end of the Act.The plot line is starting to really come together, and become complete. I am looking forward to act 5.