For the third ending, keep Adrien's affection low as possible and do the same for Ian. Take Ian's pill and spit out Adrien's pill. Kill him, then a different route will let you interact with his body where you would be able to take the key. Exit the room, proceed to the door in front of you using the key you just took and call oliver and tell him the address. After that, walk out and find Ian. For the fourth ending, follow the same step as the third but keep Ian's affection high.