I quite understoof that bit, she pressed him for answers about there finances and should she be worried and he fobbed her off, she got so frustrated that she ended up screaming which since she has never asked him any questions before must be quite a shock to Peter to be questioned!
i have lost my temper so much that i have ended up screaming at my husband as he just aviods the questions and doesn't listen to me as he doesn't want to face the truth, so i can see why she would have that reaction if everyone around her is lying and ignoring problems.