No, I'm not assuming that, but it does appear to me that the scene would have been a lot less unpleasant if Mr. Bennet had resisted the impulse to stir his wife up by playing on her worst fear. For example, Kitty would probably not have been snapped at for coughing.

I think you are making a mistake to assume that Mrs. Bennet always was as she is now. She probably never was and never could have been a model of calmness and good sense, but for the past 25 years, she has lived with a man who got amusement out of stirring her up. I can't see how that could have helped the situation, and I think there is a great possibility that it made it worse.