Chloe,
you mentioned Second officer and also Cadet Program, which one exactly are you referring to. Those are two different program at cathay pacific from what I know. The cadet program are basically for HK Residents who doesn't have no Pilot license (Ab-initios) and thats the folks that need to repay money, which comes out of the salary im told. The SO position however are for CPLMEL holders and if selected its about 8-10 weeks of training in FTA adedaile and don't think you have to repay anything. Leaving the company before upgrading to Jr. FO which could take between 3-5 yrs wouldn't be a sensible thing to do becasue you wouldn't have logged any hours and like
pilotchute said, its a no no in FAA Land. All the best
Cheers