Midway through the level you will find two rotating sections of platforms (A and B) to sides 1, 2, or 3. To clear each platform, you'll need to charge up a Pylon with a Charge Cube on each of the platforms for each of the numbered sides (Line up platform A and platform B with the same number. Rotate them to the new numbered sides and match them.). When you charge up the correct station you will see a short cut scence of a light turning green or a gate opening (depending on which platform and side it is). If you are not sure that you have done a side, go back to the tower and check the section control station. Completed sections are green, uncompleted sections are red. Once you cleared all 3 sections of both platforms the secret area and achievement will unlock.