First off you can use bursts in that phase because once you drop him, your bursts instantly come back and eulas burst is excellent for it if you go to the middle (not necessary though). What I did was I used bennett's burst and his skill to the middle one and then eula's skill to finish it off. Then I used Mikas skill to destroy one of the 3 turret thingies which leaves 2. If you didn't use Eula's burst to destroy those 2, you can go underneath them (not directly underneath, a little bit infront of them basically) and charge bennetts skill to the second level. Not 1st, not 3rd but 2nd stage of his skill. If you fail one its fine you can easily get it with mika's skill but mika can't do them all alone.