Roy knew how Dinah felt about Cheshire. Dinah tried, in every way shape and form, to be as accepting of the mass murderer as she could because- at the end of the day- she had done one thing that made up for all of that, that made her life valuable. She gave the world Lian. Usually, Dinah tried to keep her more negative opinions about Cheshire to herself and to give Roy the benefit of the doubt-- he was a good kid man person and he would only ever do what was best for Lian.
These were not usual circumstances, however.
Dinah glared at Roy and smacked him lightly on the arm, "Are you crazy?" Because clearly he must be crazy in order to let Cheshire into their house while everyone was at their most vulnerable.
Okay. Teenage Dinah needed to reel it back in because somewhere, adult Dinah was facepalming.