[Allison is fuming, and she wishes that this were in person so she could just rumor him and get it over with but given the glibness of his answer, she thinks (hopes) that he might not have realized the full damage done.]

You do realize that you didn't just erase his memory of Vanya's presence here, in zombie land. You fucking erased her from his entire life. He didn't even know he had another sister.

[She's trying to give you the benefit of the doubt here, Mingyu, but if you prove her wrong, she'll really make you tired of the Hargreeves. Hopefully Five hasn't told him about her particular power.]