Don't worry, OP. Mara will tell him it's a good and noble thing to kill the innocent. She did for years. I think she secretly wants Ben to be bad, because it's a situation she can relate to. When people become parents, lots of their own childhood insecurities and issues come to the fore. Mara seems content to have her very young son hurt others, to look like her, be her replica. She gets steamed if anyone suggests she's not doing enough to curb her bratling.