Moriarty smiles when Holmes kneels down, recognizing the body of his pet is still and lifeless. Now this source of irritation is gone, and they can go on with their game, can proceed their dance around each other, none of them able to gain a permanent victory.
Moriarty watches his rival from the distance, wiping debris from his Westwood suit. Moriarty smiles. They will be able to dance for years, a long-lasting source of thrill and amusement for the both of them.
He walks closer, addressing his rival with well-chosen words, meant to challenge. His smile fades. Holmes is not reacting, tries to breathe life into the battered body in his arms instead. Moriarty is irritated. Why doesn´t he leave the pet behind, now that it´s damaged and not useful any longer? Moriarty does not understand because unlike Holmes, he really is a sociopath. When he sees Holmes´ tears, Moriarty realizes he has underestimated the influence of the pet. He stares, gaping in disbelief, when Holmes lifts the body carefully, staggering past Moriarty without even looking at him. Moriarty thought the game was just between the two of them, never expecting plain, boring Watson being more than a pawn in it. But it seems Watson has been a player Moriarty never knew about, and now Moriarty has been bested.