Look for a way past the barrier to venture deeper into the base.
- A door will open in the left-hand wall if you are looking at the shield wall.
- From this newly opened door you will find yourself in the large room.
- You will encounter Warden Derg, Psions, 2 Legionaries and a Centurion.
- Defeating Derg will drop a another Firebase Security Code your usage.
- Return to the previous room.
- Go back to the shield wall and approach it.
- With the security codes in your possession, the wall will deactivate.