In the Blue Universe, there is a "Tulip Saloon" bar in the background during the intro scene and the elder widow has white tulips in a vase behind her in the last scene.
Walter says, "I asked for a sign of forgiveness, but I got nothing." He is talking about a "white tulip", which (when Peter was in the Blue Universe) Walter did in fact receive - as a drawing of a white tulip due to the events from the episode.