Dialog 1 hit below the belt [ アンフェアなことをいう、卑怯な手を使う ]

Angela:Why aren't you eating your chicken tonight?
Yukio:The chicken lacks flavor. It needs more spice or something.
Angela:What do you mean it lacks flavor?! I learned how to cook chicken from my mother!
Yukio:Well, your mother isn't a very good cook either.
Angela:Ooh! That's hitting below the belt.

Dialog 2 out of left field [ 唐突に ]

Angela:Thanks for being a guest in my class today. The kids really liked you!
Yukio:I really enjoyed answering their questions about the US, but a couple of their questions were out of left field.
Angela:You mean when Kouki asked if you eat rice or bread for breakfast?
Yukio:Yeah! Also, when Megumi asked me what my blood type is! What was that all about?