Dagalur Goth

Ever notice a mumakil, doesn`t attack a horde of soldiers, but that he targets a single soldier in the horde ?
The mumakil rises up to smack him with his tusks, but then the archers on his back ( or another one of your units ) kills that ONE soldier the mumie targeted, so the mumie instantly pops back to basic idle anim and starts another attack, which looks very bad I think, it`s also stupid because that one soldier got killed, but if the mumakil had finished its attack it certainly would have killed 2/3 other soldiers in the horde.
The same happens for sauron`s mace swipe.

I saw this "MustFinishAbility = Yes" somewhere in a special ability, could that be used on the basic mumakil/sauron attack to make it more functional and less ugly ? If so, how would you aply it ?