-( Story related, cannot be missed )-
After learning from Mo of the secret passage into the Corley building, go back to the main screen. To the left edge of the building will be an exit arrow pointing right signalling the back side of the building. Here, you'll see the green meters that were talked about as well as a large crack. The sweet spot will actually be located nearer the meters. If you find the discolored rock in the wall by following the crack to the left, make sure you give it a swift KICK right as the meters stall in the black zone. This will open the hatch for you.