Especially since I think by the end of Crisis Core, Zack's more than a match for Genesis and Angeal. Who needed all the alien dna, this kid did it through sheer backwater expert! Also I'm thinking I can make use of Sephiroth's .. apparently dim grasp on where the line is between 'friendly spar' and 'obliterating the junon canon'. Other people might notice something is awry and put an end to it before things escalate, he might decide Zack's just putting more effort into it for a better scuffle.

We'll need to find Zack a serviceable weapon Masamune can't just cut in half.