That is a good plan for your assassins, they will be Silenced and Dead on the field of battle. There will be other bodies next to them. But it will be nothing more than a suicide mission. I have more than willing soldiers to give their lives to prevent the Empire and your group of assassins to rule this land. The Horde will destroy and get their rightful property back.
The field will be full of corpses, it will be a shame to have to pass yours as we continue to move forward and take their stronghold.