Since he himself cannot directly accuse the King, he will use the actors to do so silently.
Other critics argue that the King does not see the dumb-show. Because there is no text in the play which describes what Claudius is doing at the moment that the dumb-show is being enacted, it is impossible to say one way or the other. The "second tooth" theory is the more widely accepted theory, and it fits with the theme of silent representation of support being taken away. Just as Hamlet silently displays for Ophelia his loss of sense, structure and support; just as the ghost silently displays for the watchmen his loss of primacy in Elsinore by wandering without purpose along the battlements, so too does Claudius silently react to the dumb-show, attempting to swallow this sudden and startling depiction of the horrific claim he has been attempting to hide for the entire drama.
The fact that Hamlet precedes the "Mousetrap" with the dumb-show marks him as an expert director, a dramatist of the first rate. He does not have his players launch immediately into a representation of Claudius' murder, but rather whets the appetite of his audience by first giving them a silent prologue, in which the murder is pantomimed. Its effect is discernible through Ophelia, who asks, "What means this, my lord?" (3.2.157). She asserts that in the dumb-show is the argument of the play and in this assertion she is correct, and doubly so.
First, she is correct because the dumb-show depicts silently the action of the "Mousetrap" as was the tradition of dumb-shows as prologues at that time in England. Second, she is correct because the dumb-show depicts not just the argument of the "Mousetrap" play but also the argument of Hamlet as well. The argument of the "Mousetrap" is simple: the king has poisoned his brother. The argument of Hamlet is more complex, but the dumb-show illustrates it no less: Elsinore is covered over by lies; there is no place for truth to assert itself. For order to be restored, therefore, truth must be made known in some other way than the normal course, which is through speech. Silent reflection becomes the mode. Hamlet is in a continual mode of reflection throughout the drama. He cannot love as he ought, because his fiance (Ophelia) has been silenced (so to speak) by her father Polonius. He cannot accuse the king and his mother the queen as he ought, because both insist on wearing a mask of merriment and insisting that all others do the same. He cannot do as the ghost bids him, because he feels the need to discern the spirit of this motivation, whether it comes from Heaven, Hell, or both (and if both, what to do about it). Because life at Elsinore has seemingly lost all objective sense, Hamlet must view things as though through a mirror. Thus, when Ophelia identifies the argument of "the play" in the dumb-show, she speaks on two levels. As Maurice Charney states, "There is a Hamlet of words that we all know almost by heart, and there is a Hamlet without words that may be more unfamiliar to us, but these two Hamlets cannot be separated in the play we see acted on the stage" (457). This point underscores the observation by Anderson, that there are almost two hundred references to the eye and/or the ear in the first two Acts of Hamlet alone (Anderson 301). As she states, the dumb-show is carefully juxtaposed to the "Mousetrap" in order to dramatize "the functions of the eye and ear and of the relative effectiveness of the two forms of drama" (301). It also draws attention to the impossibility of ever really silencing the truth.
In conclusion, this notion of two Hamlets, a silent one and a dramatic one, fits the theme which has been elucidated here, just as the dumb-show fits to the main play by acting as a prelude. Indeed, such was the common practice in English theatre, with these dumb-shows even being enacted on a separate level of the stage entirely. This may well explain the reason for Claudius' lack of reaction to the dumb-show, too. As Henry David Gray asserts, "Whatever difficulty there is in the way of this explanation could be overcome by supposing that the throne chairs of the king and Queen were placed in the inner stage, as they would be, I presume, in order that they might be removed and the prie-dieu substituted for the next scene, and that the dumb-show was acted on the upper stage" (51). Thus, even from a technical standpoint, there is no need to be shocked by the King's lack of response to the dumb-show. Any number of reasons could explain it. What is important, however, is that the dumb-show reflects the "silent treatment" that many of the characters in Hamlet are forced to undergo, whether voluntarily or under orders (as is the case of the watchmen) or in order to keep their consciences from attacking themselves (as is the case with Gertrude and Claudius). Hamlet's silence is broken with the arrival of the players: his "vision" is restored, and the dumb-show begins the process of revelation.
Anderson, Mary. "Hamlet: The Dialectic Between Eye and Ear." Renaissance and Reformation, Vol. 27, No. 4 (1991): 299-314.
Boyce, Charles. Shakespeare A to Z. NY: Dell Publishing, 1990.