This mission begins in the same arena from the previous level. Don't hit the centerpiece yet, instead head over to the large gray bump which holds Chrono Heart. In order to get it, you have to get three enemies to hit it either using High Time or Stinger. Now, when you slash the middle eyeball you’ll have three minutes (varying on difficulty) to defeat all the enemies they’ll send your way. Try and use Devil Trigger to save you some time. Once you’ve finished, hop down the portal where the centerpiece once was.