User blog comment:Matt Hadick/Ultimate Battle Final Round/@comment-88.104.102.241-20130711204231/@comment-4738647-20130711234130

The matrix is used to light the darkest hour. If there's enough accumulated wisdom/matrix energy (it dissapeared when he cured the galaxy wide plague and took time to recharge afterwards) and the opener is a true Autobot leader (neither Magnus or Galvatron could open it) then it can be used.