The fact that she broke down so quickly and immediately was, I felt, completely unrealistic. If Semirhage's strength really lied in the fact that others viewed her inhuman, she would have never risen to her status in the first place. By using this method, one makes insignificant the fact that she was (I presume) a genius, incredibly powerful in the One Power and one of the foremost leaders in understanding human physiology--with an evil twist. If all that matters is how others view her, then Semirhage had no substance beneath her veil of power. And what I think the actual case is that the Forsaken are not simply veils of power: they are the cream of the crop, the pinnacle of cunning, power, and brutality. They have real power and skills.

This scene demonstrated that Semirhage is not the cream of the crop--that she's in fact a pathetic weakling who only finds strength in others' opinion of her. Such a character would never actually reach her status in the Wheel of Time.