In this scene. It describes the symbolism blood and Macbeth. His guilt and his hatred for King Duncan, how he acted and covered up the scene of the murder.
At the start of the scene. The Night Porter/Gate Keeper, was rambling on about something that went on last night. The thing he was going on and on about was the feast. The night when Macbeth had killed Duncan (Act 2 Scene 2 reference.) Then Macduff and Lennox enter the castle, they were going on if the king is asleep (They are referring to Duncan.) Then Macbeth enters. In the process Macduff finds Duncan’s body, dead on his bed. He runs out and reports it to the rest, now going to guilt from Macbeth he plays dumb, like nothing had happened, he says “O, yet I do repent me of my fury, That I did kill them.” He plays dumb like this to hide his guilt of the scene he has made, he then walks off. While Donalbain & Malcolm then discuss who did the murder. If it was them or if it was a lie.