Locate the personnel manifest | Mission 6: For Bella A: CM Guide

Take the stairs leading to the science building. Go straight ahead, but, after receiving a warning about an active sentry turret, crouch under the armory's windows (the above screenshot).

Turn left and enter the armory. Approach the turret to disable it, then look around the room to locate the second Audio Log, pictured above. Go back to the main corridor and move forward. Stop when you reach the area with two new turrets.