"Hiding away a part of himself," Erik replies, knowing that he will not abandon Charles' identity, but he feels utterly inclined to blast his idiotic decisions on the matter. "He bears a gift, the same as I do, but he would rather lock it away." And even though Charles has explained to him the reasons why, he cannot help but feel betrayed to his very bones. There are too few of them and Charles shows he does not want to be like them.