The following page contains a walkthrough of the Detour main quest in Prey. The quest is given to the player after meeting January in the Talos 1 Lobby (or, alternatively, after searching the destroyed operator - if you skip the January conversation). This is a lengthy mission that requires getting to the archive located in the vicinity of Arboretum. Since the main elevator in the Lobby is out of order, the player will have to make their way through two other locations - the Psychotronics and GUTS.
- Checking the elevator in Talos 1 Lobby
- Reaching the Psychotrinics
- Finding the psychoscope
- Callibrating the Psychscope
- Complete the Live Examination Procedure
- Reach the passage to G.U.T.S.
- Going through G.U.T.S. and reaching the Arboretum
- Reach the entrance to the Deep Storage
Checking the elevator in Talos 1 Lobby
This objective will only appear on your list if you have never before discovered that the lift cannot be used yet (when exploring Talos I Lobby). Go one level down and examine the elevator near the reception (the one that goes to Arboretum and the Life Support level. Talking to January wll let you discover that the elevator is inactive (you will be able to repair it after reaching it from the Arboretum).
Reaching the Psychotrinics
That keycard that you got earlier can be used in the north-western part of level one of Talos I Hall - the doors that should be opened are shown above. There's no need to hurry getting to this place, since in the meantime, some Phantoms and Mimes can appear here. Stairs will lead you to the new location, but be careful: it's possible that a new, strong monster is at their bottom. Kill the Phantom or try to bypass it using the metal elements at the roof. Go through the door to Psychotronics.
Finding the psychoscope
Soon after getting to the Psychotronics, you will go by a security station and reach a place, moment, when you can take two routes. The one on the left leads to the women's toilet, and there are no Phantoms or Mimes there. The one on the right, leads to the men's room. There are no monsters there either, but there are some crates blocking access to it. You can move them using Strength.
Regardless of your choice, you will reach a decontamination chamber and learn that in order to pass through, you will need a psychoscope. Go to the men's room again and find the hole in the floor shown above. This will get you to a tunnel going underneath the psychotronics.
After finding the tunnel, approach the big hole that was sealed with a GLOO gun. A couple of Mimes will come through this hole. You need to defeat them (use the flashlight - it's pretty dark). When you manage to do that, go to check the area from which they came. You have to licate the corpse of Janos Jozsef, shown above. On him, you will find 2 neuromods and the psychoscope we're looking for. From now on, you can use the device to scan enemies, people and machines, which will allow you to analyze their strong and weak points as well as grant you access to alien powers (that will happen in a minute). Additionally, you can now install psychoscope chipsets (initially only two; further slots can be unlocked with developing Psychotronics), which work analogically to the regular Suit chipsets.
You can start heading back, but beware - a Phantom is likely to spawn in the men's room. Don't let it catch you by surprise when you're climbing towards the exit. You can now go through the decontamination chamber and use the gravitation shaft to get to level 2.
Callibrating the Psychscope
When you enter the atrium Alex Yu will contact your character. You learn that you need to calibrate the Psychoscope which is a part of a tutorial during which you learn how to use this device which can help you to unlock new alien abilities. Examine the capsules in the central part of the atrium. Keep revealing new capsules and scan the Phantoms held inside of them. After scanning two of them you unlock the base ability called Kinetic Blast I. Alex also gives you the code to the safe inside Dr. Kelstrup's office, although going to that location is completely optional (the location is a part of Dr. Kelstrup's Neuromods side quest).
Important note - When you use Psychoscope you only unlock alien so you can later buy them. In order to use them you must spend your neuromods. This means that you shouldn't worry about making scans in this mission because it won't hinder your gameplay style geared towards human abilities while ignoring the alien ones.
Complete the Live Examination Procedure
You can now go through the control point located in the south part of the atrium. When you reach the fork in the road it is worth to scan the Weaver from the big round room. Next, choose the right (west) path. It leads to Live Exam Area. When you get there you must listen to what January has to say and then go to the terminal located next to the big cage made of glass.
When you are in the computer's menu select the second tab (Live Exam Controls) and start the experiment. The result is that a Voltaic Phantom will appear in the room. You must defeat this monster and the best way to start this fight is to use an EMP charge or release a Nullwave (you can use a gadget or select the option to activate it from the cage's terminal). Then, you can use, e.g. the shotgun or alien abilities to weaken the creature.
Reach the passage to G.U.T.S.
By eliminating the Phantoms you unlocked the passage in the south that leads to another part of the station. Use it. There are two turrets placed near the door that leads to G.U.T.S. If you didn't unlock any alien abilities then you have nothing to fear, you can pass without any problems. Otherwise, they can treat you as an enemy and start firing at you. When this happens you can use EMP charges and attack them from a distance. Regardless of what happened you must go to G.U.T.S.
Going through G.U.T.S. and reaching the Arboretum
In G.U.T.S. you must follow the linear path, with a few small puzzles, that leads to the Arboretum. Most of the tunnels in this location have zero gravity, you can experience it right after you go through the airlock. Remember that when you fly you shouldn't hit other objects while moving fast because you can damage your suit and lose health points.
In one of the tunnels you can, for the first time, see Cystoids and their nests. Alien abilities (e.g. the basic version of Kinetic Blast) are good for destroying nests (you can also try to avoid them) but you can also destroy them by using firearms or throw petrol cans at them. As for Cystoids, they react to movement so it is worth to throw objects near them. There is a chance that they start chasing that object and explode prematurely. In both cases you should try to avoid direct contact with Cystoids because, besides losing a few health and suit points, you can also increase the percentage of radiation.
Continue flying until you reach the closed airlock. Look for an EMP charge (it should be in one of the crates) or select it from your inventory, if you have it already. Use the EMP charge on the big fan, presented in the picture above. By doing that you can stop it and move safely to another area.
An alternative solution is to fly to the closed airlock and hack into its system by using Hacking II human ability.
When you reach another airlock you must, again, make the decision about your next path. The first variant is to get rid of electrical discharges, that prevents you from passing safely. They are caused by the destroyed electrical joint box. You can fix it by using the GLOO Cannon (using the Repair ability is optional). The second variant is to take an interest in the big fan nearby. Next to it you can find Cystoids' nest. You must get rid of them first so you can go safely through the side corridor.
Soon, you receive an information from January from which you learn that an active magnetosphere can be found nearby. Ignore the new airlock on G.U.T.S Research Level (you can't hack the reader) and fly to the side area with normal gravity. Enter the Magnetosphere Control Room, found behind a giant glass. Go to the adjacent room and use the stairs. On the upper level you must destroy Cystoids' nests because you can't go around them - the room is to small.
When you secure the upper level you should stand near the opening that leads to the Magnetosphere chamber. WAIT until it ends its cycle - wait the end of the countdown which is proceeded by a release of a shock wave. You must quickly enter the chamber and fly to the Anders Kline's corpse, presented in the picture. Examine them and get Maintenance Tunnel Keycard (you also get, among other things, 2 neuromods). Warning - If you don't leave the chamber in time before the next activation then your character will die immediately!
Go back to the main tunnel and be careful because on your way to the control room you can fight, e.g. corrupted operators. Fly to the airlock and use the newly acquired keycard.
Continue exploring the zero gravity tunnels until you reach the fork in the road. Since the Arboretum is the main destination you should choose the left tunnel. The main obstacles, that you can find on your way, are Cystoids but you can also come across a Typhon Weaver. A fight with this enemy can prove to be rather difficult. When facing this monster you can use Nullwave transmitters which cause the enemy to lose its shield for a short period of time. Then, you can use whatever powerful weapon you have and deal some damage. Watch out for Cystoids send by a Weaver. You can run from them or eliminate them before they reach the main character.
After the battle you can continue flying to the area with a normal gravity. There, you find the door that leads to the Arboretum.
Reach the entrance to the Deep Storage
This is the final part of this long mission but there is one last thing that you must do which is the journey to the north part of Arboretum. During your walk you should stay on the main road and don't be in a hurry because the main character will be regularly attacked by Mimics (normal and larger ones), different versions of Phantoms (e.g. Thermal and Voltaic) and corrupted operators. In addition to those enemies you can also face the turrets if you unlocked a lot of alien abilities.
Your target destination is the Grav Shaft presented in the picture above, located in the north part of the map. It is located next to the inactive one that leads to Alex Yu's office.
After using the Grav Shaft you can try to open the door that leads to the Deep Storage but they won't budge. Next, you must examine Zachary West's body and get a TranScribe. Listen to the recording and you learn that you must get a voice samples of Danielle Sho. Getting them allows you to remove a blockade on a biometric lock. The process of finding those samples is connected to another main mission - Gathering Echoes.