In order to get out of Theta you have to get a key card from Brad , so to do that you go to the security room first to unlock his door and then head back to security to update the connector chip ,once that’s done you can proceed to the elevator and go to the transport floor all the while avoiding the blob.
Down in the subway there’s always something to hide from but eventually you’ll come to an electrical panel that you have to pump up to reset the power, after the power is reset exit the room and open the door that’s on the right and just jump off the end into the water below. Swim left and climb the ladder onto the sea can follow the catwalks around to where there are submerged boxes that you can walk across and then follow the scaffolding around until you get to the room with the emergency flush switch, flip the switch and run through the door that opened and you’ll be flushed back onto the ocean floor and then it’s just a matter of walking to Omicron. To access the power house you have to use the manual override to flush the water out.
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