Taking up an apple, he becomes Banquo; taking up a doll he is Malcolm, son of slain King Duncan.
In the scene of discovery Banquo of course appears, and his behaviour is significant.
His behaviour would be precisely that which is implied by the question of Banquo.
Eight kings, and Banquo following, appeared to Macbeth's vision.
Are we to regard Banquo as strong and noble, or blamelessly weak, or criminally negligent?
"Dis way, ma'am," said Banquo, marshalling the woman to the hall.