Macduff's sudden departure to England was born out of necessity and urgency. He wanted to urge Malcolm to attack Macbeth and reclaim the Scottish throne which had been so ruthlessly usurped by Macbeth. Furthermore, his beloved country was in turmoil. Macbeth's tyranny knew no bounds and Macduff was desperate to restore order. In this sense then, his flight had an honourable purpose and would serve the greater good. Once Macbeth has been defeated, order will be restored and Scotland's people will be safe. One cannot therefore blame him entirely for abandoning his family.
The question arises though, was Macduff foolish or naïve to believe that Macbeth would not stoop so low as to harm his family? Or is this an indication of Macduff's inherent goodness that he could not even think the unthinkable? Whatever it may be, Lady Macduff is not convinced. She is utterly distraught and resentful that her husband could have left them in such a perilous and vulnerable situation.
In her conversation with Ross (Act 4 scene 2), he tries his best to make her think differently of her husband's flight, but to no avail. When he talks about whether it was through wisdom or fear that Macduff left, she angrily replies:
"Wisdom! to leave his wife, to leave his babes,
His mansion and his titles in a place
From whence himself does fly? He loves us not;"
Ross declares that they are living in uncertain times and that they do not know what or why they fear. Lady Macduff should look to herself for not having enough faith in her husband. It is clear that Ross is desperate to leave and begs to be excused saying that things could only become better or worse. His anxiety is palpably clear and he then leaves in a hurry.
Lady Macduff is unforgiving. She is so upset that she tells her son:
"Sirrah, your father's dead;
And what will you do now? How will you live?"
To her, her husband has ceased to exist. She emphasises her bitterness later by calling Macduff a traitor - one who swears and lies. She adds that such people should be hanged.
It is tragic that Macduff never has the opportunity to redeem himself with his family, for soon after, Macbeth's assassins arrive and kill them all. Macduff is later overcome with grief and remorse when he receives news of their murder and swears revenge:
"Cut short all intermission; front to front
Bring thou this fiend of Scotland and myself;
Within my sword's length set him; if he 'scape,
Heaven forgive him too!"
I don't blame Macduff, but he certainly blamed himself and agonized over their deaths. When he first hears of their slaughter, Macduff's first reaction is that he wasn't there to help them. Furthermore, he blames himself and his trying to overthrow Macbeth for their deaths. "Sinful Macduff," he says to himself, "They were all struck for thee . . . Not for their own demerits, but for mine / Fell slaughter on their souls." Macduff never would have knowingly left his family unprotected. He loved them deeply, calling his children "all my pretty ones." Macduff mourns: "I cannot but remember such things were, / That were most precious to me." Macduff left his family to bring down his country's murderous tyrant. The slaughter of his family and entire household was so wicked that he did not even imagine it.