Lady Macduff and Malcolm both question Macduff's motives for fleeing Scotland. Think about the crimes Macbeth has already committed. Why might the nature of these crimes have led Maduff to believe his family would be safe at his castle? ... with textual evidence and explanation on how the textual evidence works.

I think that Macduff fled because he saw the murdered of King Duncan inside the bedchambers of Macbeth. He left his castle and went to England. Macduff went to see Malcolm and had offered his support in overthrowing Macbeth from the throne. Macduff did this out of revenge after Macbeth had also murdered his family.