Kazuya beating down an axe-wielding lunatic twice his size with a pair of brass knuckles. Specifically, the guy was wielding a fricking halberd.
Victorique's solution to a murderous Phantom Thief threatening Kazuya, handily putting paid to any speculation by either about her potential non-existence.
Brian Roscoe's most legendary feat of stage magic, the Felling Maria incident, in which he single-handedly stopped a German bombing raid on a convent during World War I with a well-placed projector.
Victorique and Kazuya disarming a bomb with a gun, while standing on the front of a moving train. Not to mention they only have One Bullet Left.
Cordelia finally confronting Albert de Blois and besting him in a freaking sword-fight.
Episode 17: We present Kazuya outrunning an ocean while carrying Victorique.
Many of Victorique's solutions to mysteries count even if some seem obvious to the viewer because she doesn't have the benefit of the writers making the important details obvious.