Mindjack

Simply shoot enemies (either computer or Red Player controlled) until the "Mind Slave" prompt hovers over their heads then use the Mind Slave ability on them. In order to earn the achievement you need to have 4 mind slaved enemies going at once and they all have to have been mind slaved by you personally... your partner's mind slaves don't count. Also you can't mind slave civilians that were mind hacked by Red team players. They will simply die once they've been shot.