There is clearly a marked difference in Macbeth's demeanor in Act II Scene 3 compared with his words and actions in Act II, Scene 2. In the second scene, for instance, as Macbeth contemplates his murderous action, he is ridden with guilt and misgivings. For, when he returns to Lady Macbeth after he has slain King Duncan, Macbeth reviews what has occurred and he tells his wife that he heard a voice cry
“Glamis hath murdered sleep, and therefore Cawdor
Shall sleep no more. Macbeth shall sleep no more.” (2.2.55)
and he confesses to his trepidation: "I am afraid to think what I have done" (2.2.65); he tells Lady Macbeth that no ocean can wash the blood from his hand. And, when he hears knocking, Macbeth wishes that Duncan could awaken to this sound, wishing to undone his heinous act.
In contrast to this behavior, Macbeth seems in control of his emotions in the next scene, as in the morning he greets Lennox and Macduff as though nothing has happened to their king, leading them to King Duncan's chambers, telling them that the king has not stirred yet although he plans on leaving this day. Yet, incongruously, when the two noblemen discover that Duncan is dead and the two guards have blood smeared on them, Macbeth, dissembling, confesses to having slain these guards,O, yet I do repent me of my fury,
That I did kill them. (2.3.117-118)He explains that when he saw the body of King Duncan slain and "overtook with gore," his anger overtook him and he killed the "murderers."
Thus, the character of Macbeth is completely different in Act II, Scene 2 from that of Act II, Scene 3, for he is guilt-ridden and frightened at first, but in the next scene, he appears to be in control of his feelings, although his are incongruous actions.