Answer:
Act IV sees King Claudius banish Hamlet to England, eliminating him from Denmark and the play. We begin to highlight "the rotten thing in Denmark as well as other characters that were left behind, such as Ophelia's "crazy daisy" moment and many more. Characters and events are also shown in the scenario. Allowing observers and readers to perceive the characters' struggles.
Laertes struggles with Claudius as Ophelia goes mad. Most essential, we observe Claudius' pain at Hamlet's death.
Hamlet's absence in this moment is cleverly designed as we can see how things are starting to go wrong in Denmark.