Say Zab got through to round 3..

Tszyu would come out at the bell, swinging and would have banged Zab out within the first minute.

Zab was 'walking unconcious' when it was stopped - he disputed it so savagely because he could remember little of the KO.

I think Zab would have been really really hurt and knowing how he gets into his shell when he gets hurt, would have been clubbed to death with body shots until the chin poked out and Tszyu would have unscrewed his head.