One ambiguity of Act II is why did Macbeth not also kill Malcolm and Donalbain when he had the chance. When Duncan named Malcolm the Prince of Cumberland, he was rightfully next in line to be king:
"We will establish our estate upon
Our eldest, Malcolm, whom we name hereafter
The Prince of Cumberland..." (I.iv.33-35).
However, after the murders of Duncan and the servants, who were initially blamed, Malcolm and Donalbain agree to flee the castle, and then suspicion drifts to them. Macbeth's strategy in not killing Duncan's sons is a big question mark for audiences and readers alike in Act II.
Ambiguity in dialogue also abounds throughout Act II. One great example occurs when Lady Macbeth says:
"Why did you bring these daggers from the place?
They must lie there" (II.ii.61-61).
Lady Macbeth's words carry double meaning. She could mean that the daggers need to rest next to the bodies of the servants, but she could also mean that the daggers need to 'lie' as in speak untruthfully about the crime that has been committed.