go up three ramps from assisant danforth. when you are on the third ledge, go straight and make a right turn. it is at the very end where you cant go any further :D
Go back to Robert Lancaster. From his position, go up a ramp, turn around and go up another ramp. Turn around and go up another ramp again. Continue in that direction pass the scaffolding, turn right at the corner and continue. Beetle will be there about a quarter to a third down the "hall".
