I got mine out of luck...so good luck

(PS it doesnt matter if the opponent you do disarm and destroy to has a weapon..all that matters is you do the move.)
Come out of the gates swinging ..puul em in..slam em down, throw a batterang...get in all of the combos..reverse..fly over their heads...destroy weapons when you see one and get rid of he fire extinguisher in the earlier rounds - let them grab it..and dont destroy weapons leading up to the 3rd round i believe it is..dont remember