In Act II of Macbeth, in what ways (besides murder) does Macbeth's behavior become unheroic, even unmanly? What do you think causes this behavior?
Act II of Macbeth confirms Macbeth as tragic. Having so boldly served his king, he now embroils himself in his obsession to ensure that the witches prophesies come true. Initially, he is reluctant to go through with it but,having steeled himself to do so and on the ringing of the bell, he not only murders Duncan but Duncan's guards.
Macbeth is definitely a contradiction. It is debatable whether he feels any remorse after killing Duncan or - more likely - fears being caught and this is the reason for his confusion. Any indication of regret
Wake Duncan with thy knocking! I would thou/ couldst!
just further shows that he is faint-hearted. He is not haunted because of any realization of the heinous crime he has committed but the possible consequences should he be caught - definitely indicative of a cowardly individual and nothing like the hero he was on the battlefield.
The trance-like state renders him incapable of rational thought, especially as he is convinced that he hears a voice:
Sleep no more!... Macbeth hath murdered sleep.
Macbeth is so self-absorbed, that he thinks the whole castle could hear the voices. He is so affected by the witches prophesies and by his wife's control over him.
In the frenzy - and perhaps because of the vision of the daggers as they beckoned him before he murdered Duncan - Macbeth takes the 'murder weapon' with him.
In his tormented state, Macbeth leaves the murder scene carrying the bloody daggers
and Lady Macbeth, dealing only with the situation at hand, has to step in: realizing that Macbeth will not return the dagger as he is too scared,resolves to do so herself.
This shows Macbeth's weak nature and cowardice and is not at all chivalrous. Macbeth should not have allowed his wife to place herself at risk and in danger of being caught.