To what extent has Macbeth changed in Act III , scene iv of Shakespeare's Macbeth?

In the famous Banquet Scene(act 3
scene 4) Macbeth addresses the nobles in quite a composed, hospitable manner, and Lady
Macbeth also plays the role of a perfect hostess. But as the first murderer appears near
the door to report that Fleance has escaped though Banquo has been killed, Macbeth seems
to plunge into a paroxysm of fear. His fit of fear gives rise to the hallucinatory image
of dead Banquo. This ghost of Banquo virtually exposes Macbeth's crime of Duncan's
murder before all the nobles of Scotland. The ghost appears twice and shakes his gory
locks at Macbeth whose terror-stricken words and abnormal behavior lead to the
abandonment of the Banquet. As the guests are sent away by Lady Macbeth, Macbeth decides
to meet the witches to know " by the worst means the worst". This decision marks the
approaching doom.