- Killing Polonius: In a fit of rage and confusion after confronting his mother in her chamber, Hamlet mistakenly kills Polonius, who is hiding behind the arras. This impulsive act has far-reaching consequences, including Ophelia's madness and death, Laertes' thirst for revenge, and Hamlet's own guilt and isolation.
- Leaving for England without delay: After Claudius reveals his role in his father's murder, Hamlet decides to leave for England immediately, following the orders of Claudius. This hasty decision prevents him from taking any immediate action against Claudius and allows the king to continue plotting against him.
- Arranging the play within the play: Hamlet quickly organizes the performance of "The Mousetrap" to expose Claudius's guilt. While this plan ultimately succeeds in confirming Claudius's guilt, it also puts Hamlet in danger and arouses Claudius's suspicions.
- Killing Rosencrantz and Guildenstern: Hamlet rashly sends Rosencrantz and Guildenstern to their deaths when he alters the letter they are carrying to England, condemning them as spies. This action shows Hamlet's willingness to take extreme measures without fully considering the consequences.