First, I think she was startled.
Second, that is a clip that has been played with to extend and repeat her reaction.
Third, the original clips, I have seen two from different angles, show an exaggerated reaction to a couple of reporters bombarding her with questions at the same time.
Fourth, I am not a medical doctor so I don’t know if her reaction is “normal” or pathological.
I do think she is ill. I think in addition to her pure evil hatred and ambition, she is guilty of treason, murder, theft, and fraud. If there is a devil, I think she has sold her soul, intentionally and with knowledge.