My God, What Have I Done?: He has one of these moments before the start of the game, upon realizing that his research on Las Plagas was being used to make them stronger and more infectious.
This was likely due to having once been host to a full grown Plagas.
Heroic Willpower: Before the game, he was fully infected with a Plagas, but his Plagas acted so much like him that it killed itself to free him from Saddler's control.Heel≯ace Turn: Although he is unusual in that his happens before the beginning of the story proper.Luis: "I see the President has equipped his daughter with ballistics, too." Given how he blames himself for the impending disaster with the Las Plagas release, it makes sense.