Hamlet's struggle in the first half of the play is whether or not the ghost is speaking the truth. If the ghost is truthful, he wants nothing more than to avenge his father's death. Since he already despises Claudius for marrying his mother, he has no problem getting revenge. However, since Hamlet doesn't want to kill Claudius while he is praying, Hamlet waits too long to act. When he does act, he kills the wrong man (Polonius). This is the point of no return. Because Hamlet kills Polonius, Ophelia kills herself and Laertes vows revenge. Because Claudius is getting desperate to get rid of Hamlet, he conspires with Laertes to the match with Hamlet, and decides to poison Hamlet's glass. We can conclude, then, that Hamlet's inaction directly relates to Ophelia, Laertes, Gertrude, and Claudius dying.