Donnie’s need for knowledge has driven him to do the unthinkable. He’s started experimenting on people. He knows, morally, that it’s wrong but he can’t seem to stop himself. He doesn’t want his family or friends to know about this but if they do find out… well perhaps his experiments can go from just physical experiments to psychological ones as well? Just to make you don’t tell the rest of the family of his unsavory deeds. He’s always been curious about effects of Stockholm syndrome after all.