Lady Macbeth and Macbeth had originally planned to murder Duncan in his bed and to smear blood on the faces of his two attendants so that it would be supposed that these men had been bribed by someone, probably the King's own son, to kill him. Then the Macbeths planned to remain in their chamber until the body was discovered, whereupon they would make an appearance and pretend to have been sound asleep. However, Macduff's prolonged and unanswered knocking at the gate in the early morning forced Macbeth to come down to see what was happening, and once he had put in an appearance he was forced to be present outside Duncan's chamber when Macduff discovered the body. This proved to be a partial advantage because it enabled Macbeth to rush inside and kill both attendants before anyone had a chance to ask them questions. Otherwise, the murder went as plaanned. Macbeth should have murdered Duncan's two sons that same night, since he had no chance of claiming the throne otherwise. But this was not discussed in the text. Presumably the Macbeths thought the sons would flee or be disqualified from inheriting if thought to be guilty of their father's murder, but this seems like very careless planning and wishful thinking.