"Ni how", as many readers might know, is a greeting in Mandarin... depending on how one pronounces it that is. Did Zac get it right in his sucky attempt to impress Jade Arrow... eh, probably not! In this scene, Jade Arrow, who has already graduated from the Academy chooses to refer to Zac as Cadet Breen rather than The Whizzard, even though he is a senior cadet in uniform - Nadine couldn't get away with that but Jade Arrow knew she could!
Also, proof here that the Fast Club do their background research on potential members before inviting them to join.