Ian was quiet as he drove Mills' car. He was upset with Mina, but he really had no reason to be angry with her. His concern was that someone would trace the disappearance of Lydia and Gregory to the woman and start a whole new mess for him to seek help from Cam to hide.
Although Ian could make any criminal charge disappear, he did not want to go after yet another family on Mina's behalf. There was a limit to what he could do, and with him having weakened the Lee family's appearance, a lot of other families were growing bold.
Even Drax knew better than to just decimate the Sims. They had their hands in a little of everything, and their complete disappearance would financially hurt too many people. Ian began to bicker with Mina, because he just did not understand why the woman seemed to be a magnet for trouble, and it was the only thing he could think to do.
"You are acting as if I knew."