This sentence is very ironic. Macduff says he won't be able to bear the news of what has happened. He says it shouldn't happen again. But what he doesn't know is that she took part in the murder. He planned it and helped us. She already knows about the murder. Act III: Banquo suspects Macbeth of the king's murder. Macbeth then feels threatened by him and hires criminals to kill Banquo and his son. In the act the son runs away and runs away. Macbeth then hosts a dinner party and sees Banquo's ghost and starts freaking out. Lady Macbeth covers up the act by saying that he is simply sick. Macduff does not show up because he is headed to England to get help because he is suspicious of Macbeth. I'm in the blood, I've entered to such an extent that, if I never had to wade again, coming back would be as boring as going forward. In this line Macbeth feels that he is up to his neck in shit. He is confused about what to do next. He is so consumed with guilt over the murders that he cannot see clearly what to do next. So he decides to go and visit the witches to find out more about what it's all about