After you destroy all the turrets,a little clip will start. After it you will begin to fight Jazz. Immediatly transform into vehicle form and fly away. Make shore you are always move up and down or left and right, because the turrets will fire at you. As you fly away look for a little building thing that leads underground. MAKE SURE YOU STAY IN VEHICLE FORM! Then fly down the into the buillding and continue flyind down until the clip of Jazz dyind starts.