The first secret can be found around 18:30 in the Video above.

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Follow the objectives until you reach the section where you must activate the Pump Valve. After activating it, reboot the console.

Return to the elevator and head left, where you've cleared the gas and can now proceed safely.

Upon entering the next room, follow the the Blue Electric Cable to the right. You'll find a passage leading underground, which will guide you to the first secret.

The 2nd Secret can be found around 43:40 in the video above.

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Follow the objectives until you reach the point where you have a video call with MIA, who informs you of her need for rescue, triggering a 30-second countdown.

Once the countdown ends, proceed forward towards the gate directly ahead. Instead of going left, head through the gate on the opposite end to your right. Upon passing through, immediately turn left where you'll encounter explosive Red Barrels. Shoot them to unlock a hidden passage in the wall, leading you to the second secret.

The 2nd Secret can be found around 9:45 in the video above.

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Follow the objective until you reach the part where you have to Activate the Habitation Console.
After activating the console, move to the corner to your right, the corner behind the screens where you can activate the Inspection Arm Power Control which will activate a small screen near the big pump we just activated, use the Arm Control to bring up the 3rd Secret.

Habitation Console:

Inspection Arm Power Control

Arm Control

The 4th Secret can be found around 12:30 in the video above.

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Follow the objective until you reach the part with " Activate the Genetic Tracking System "
Don't activate it yet, turn around and go forward until you reach a narrow corridor, follow the narrow corridor and stick to the right wall.

You will reach a room with a broken double door, an alien ambush and some breakable glass with a Rocket Launcher on the other side, if you pick up the rocket launcher a secret door will upon revealing another corridor, follow it for the 4th Secret.

Genetic Tracking System

Narrow Corridor after you turn around at the Tracking System

The Rocket Launcher behind Glass

The Corridor leading to the secret after picking up the Rocket Launcher behind the Glass

The last secret can be found around 14:30 in the video above.

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Follow the objective until you reach the part where you have to cross a Bridge with blue electricity.

After walking past the bridge, turn to the right and activate the Elevator Control

Go to the left and use the Elevator Control

Follow the path until you reach the last Secret

Please consider following the Silver Crusade: