3 Dog Tags
Disembark from the elevator and proceed along the path. You'll encounter more xenos along the way. Just take them out until you reach the next gate with a mounted auto-turret. Stay out of the light to avoid getting spotted and fired upon.
Circle around the vehicle and enter the cavern. Make your way to the exit and you'll find a sealed gate. Before heading forth, turn to the right past the vehicle to find a full body armor to the left. Just beside it is the mission's first dog tag.
Go through the next outpost and avoid the auto-turret spotlight again. Open the other door to exit and fight your way through more enemies. Continue until you reach the breached gate and get past the guards. Enter the ramp and proceed to the medical bay for a scene.
After the scene, collect the items and head upstairs. Continue to the control switch then turn right to find another dog tag on top of the console. Deactivate the safety lockdown and get inside the lab. Head to the left to find another audio log.
Kill the guards in the lab then go downstairs to find more host subjects. Open the door and kill the two guards. Proceed to the operating room where you'll find another laptop near the operating tables. Examine it to get the second audio log.
Continue along several rooms and kill all hostiles. Continue until you reach an examination room. If ever the enemies reach for the alarm and successfully activate it, kill them quickly and deactivate it. There aren't any Collectibles in the next few rooms so continue forth until your objective is updated and you exit the facility.
Move along until an APC appears. Run to the left to avoid its deadly hail of bullets. Encircle around it until you reach the open area. More enemy troops will appear. Take them out while taking cover to avoid too much damage. Use the crates as you move to the left where you can find a broken fence you can enter.
Continue forth and take out the enemies. The APC will move back to the next area. Shoot the barrels beside it to push it back under the giant crane. Heavy RPG soldiers will exit from the facility ahead. Take cover and take them out, along with the other PMC foot soldiers. Move from cover to cover and keep right until you find the crane controls. Use it to destroy the APC then enter the next facility.
Once inside, continue past two doors until you reach an area with several smaller rooms. Turn to the left to find a monitoring room and the mission's last audio log.
Proceed to the module control room and kill the personnel there. After getting your objective updated, open the door beside Oneal and go downstairs. Once you've reached the lower floor, turn to the right and look inside one of the open boxes there to find the last dog tag of the mission.
Find the first power cells in the lower level by accessing the door near the stairs. After disabling it, go upstairs and look for an opening on the floor. Drop inside and kill the guard to disable the second power cell. The door to the third power cell will be open by now. Get past the main stairs and enter the room. Disable it to complete the current objective.
Get back to the module control room and pull the lever to disable the power and complete the mission.