I think lady Macbeth is presented as cruel in this scene and this is shown as in this scene as she says things such as when she says “come to my woman’s breasts and take my milk for gall you murdering ministers.” This uses techniques such as alteration and metaphors to make the reader picture lady Macbeth as cruel, like when she says take my milk for gall this is showing that lady Macbeth wants to take all the compassion away from here, and she uses milk to show this as mothers milk is usually depicted as nurturing and caring and she is saying that she wants all the caring taken from her and replaced with poison. I think Shakespeare did this as this is the first scene lady Macbeth is in and she is always more willing to kill than macbeth throughout the play so showing her for the first time in this scene and have her do a soliloquy in which she says all this will set up her character that is cruel and pushes Macbeth to a darker path throughout the play.