. . . now you don’t.
And that’s one of my favorite things about the Zeffirelli / Mel Gibson Hamlet (the character, not the play). This Hamlet is sneaky.
There are great advantages to portraying a Hamlet who overhears a lot of what goes on in Elsinore. It helps motivate his hatred of Polonius, it helps us understand his suspicions of Ophelia, and it gives him a greater rationale for putting on the mad act.
Of course, that depends on whether we think that Mad Max is capable of merely acting mad and not being mad.