After completing the Finnish Tango, you will start the second last mission of Control; Polaris. The tape player you have now will grant you access to the maze and this Control Polaris walkthrough guide will lead you through the rest.
With the tape player that was provided to you by the janitor, Ahti, you are going to go back to the Ashtray Maze. You can use fast travel to reach the Ashtray Maze quicker.
Navigate the Ashtray Maze
Due to the tape player, the music will be banging on the way through the maze and will be helping you choose the correct way only. The maze itself is very straightforward and will take you through only one exit in the end.
You are going to face enemies around the maze a few times, but that, hopefully, won’t be a problem for you. You would have to levitate at some points to reach the end quickly, but that will be it.
Once you exit the maze, you are going to reach the Dimensional Research.
Search for the Slide Projector
Inside the Dimensional Research, you are going to go inside the control room, where a cutscene will appear, showing you the absence of the projector.
Go to the Hedron Chamber. Once you go inside the Camber, you have to reach the panel. A lot of enemies are going to be dispatched in your way, but you have to go and cleanse all the Siphons in the Chamber.
How to Cleanse the Siphons
Go to the nearest Siphon and cleanse it. When you cleanse a siphon, you will have to kill the enemy wave that comes at you. Keep in mind that after you cleanse the first Siphon, you will need to clear the next three without dying; otherwise, you will have to replay the mission again.
Find another Siphon in the big room and cleanse it, and the room will change again. Look for another Siphon, go destroy the antenna and fight the enemies. Once you cleanse it, the room will change again.
To arrive at Polaris, use Levitate to climb the three columns that ascend up to one side of the last Siphon. Go and clean that as well, and with this, the Polaris Achievement will be unlocked.
The credits will start to roll, and you will see the distorted text on your screen. After this occurs, a cutscene will roll, and you will take control of Jesse for the final mission Take Control.
This is all that you have to do in the Polaris mission. Just keep fighting the enemies and cleaning the Satellites, and you will be easily completing the mission. Any failure will result in the loss of the mission, and you will be doing all this, all over again.