Ah, but Rosenstern and Guildencrantz didn't know they were part of Claudius plot to have Hamlet whacked in England (unless you've read Tom Stoppard). They were just supposed to take him on holiday. And I maintain that if Hamlet did the deed in the beginning none of the others would have been through so much suffering. Hamlet basically drove Ophelia mad. Well, him and her father's using her to run interference.