DO YOU THINK THAT HAMLET FINALLY KILLED HIS UNCLE BECAUSE OF WHAT CLAUDIUS HAD DONE TO HAMLETS FATHER OR BECAUSE OF AN IMPULSIVE REACTION TO THE KINGS TREACHERY IN THE DUEL? ACT 5 SCENE 2

I think Hamlet had always planned a death revenge, it just took him a really long time to get around to it. Hamlet got sidetracked by existential musings until he finally gets around to some actual fighting.