Scene 1: "Is this a dagger which I see before me, the handle towards my hand?" Macbeth is hallucinating. He is contemplating whether he should kill the king, he knows its wrong. He is not in control; being persuaded by evil?
Scene 2: Macbeth has "done the deed". Macbeth killed two servants of King Duncan as they saw him commit high treason(killed the king. A God-given role.) Lady Macbeth has to clean up the mess so she makes it look like the servants killed the King.
Macduff finds King Duncan Slain and blows a trumpet to wake everyone up and alarm them. Malcolm and donalbain leave as they are suspicious Malcolm to England, Donnelbain to Ireland.