The Mad Doctor

The Interpol agent Hiko is requesting our assistance in tracking down the notorious criminal Jackal and an irreputable surgeon that goes by... Surgeon. Jackal is known for getting facelifts to cover his tracks and the two are known to have been in contact.
While Hiko looks for information in the northern part of the Zone, Marked One should look for intel in the Bar.
Parts of this quest are not tracked.
== Walkthrough ==
=== Bar pt. 1 ===
Travel to the Bar and speak to Barkeep. He doesn't have any useful information on Surgeon, but suggests asking Screw and Sakharov for more specific inquiries on the kind of equipment Surgeon would have needed. After leaving the Bar, a message on the local network warns about a squad of military spotted in the Army Warehouses.
=== Army Warehouses ===
Six elite soldiers will be camping the Army Warehouses - Bar transition, and will unload their underbarrel grenade launchers as soon as they get sight of you. It's safer to enter the location from the Wild Territory, as only two of them will be on the hill next to the transition from there.
Loot the military commander for his PDA. The order on it says that they were hunting for some device that fallen into the hands of an unknown person in the Zone. Picking it up starts Mystery of the "Photon" product and unlocks the rest of Healing Prime and the Sniper storyline.
Speak to Screw. He recalls a group of three stalkers that came to him for a repair inquiry. Their generator was too large to bring in for repairs, and they went to see Syak in Radar for other parts. Screw advises you to speak to Cap as they would have passed by that area.
Speak to Cap. He did see the three; the leader is a guide named Laperouse, while the other two unknowns were carting along a large amount of equipment. Hiko will message you about his progress.
After speaking to Cap, another elite squad of six soldiers will spawn at the transition to Radar. Take them out and loot the commander's PDA.
=== Radar ===
Syak saw the three of them passing through Radar, and says he dissuaded them from going into X-10. They must have passed through Yantar after being chased by an elite military squad.
=== Yantar pt. 1 ===
Thirteen elite soldiers will be waiting in the factory above X-16 laboratory. Two have RPO-A launchers and almost all others will have underbarrel grenades. The loners will help you take them out.
After looting the commander's PDA, a stalker named Tikhon the Nightingale will message you. Go behind the bus in the [ loner camp] to find him wounded after the military attack. Speak to him and find out about Surgeon's activities in Jupiter; after the talk Tikhon dies. Hiko will message you, and encourage you to decode the three PDAs from the squad commanders. He advises to check any military acquaintances, if you have any. Meanwhile, Hiko will check Jupiter.
=== Cordon ===
Head over to Cordon and talk to Kuznetsov about decoding the PDAs. He wants 50,000 RU for information on how to do this. He says a military specialist deserted from the Zone, leaving their decoding equipment at the Agroprom military base. We delivered this case to Sakharov earlier on.
=== Yantar pt. 2 ===
Return to Yantar and speak to Sakharov. Turns out he shipped the case over to the Bar in return for the Duty security detail. The decoder will not function without a specific key that the military specialist must have known. He also offers some help in the form of information; a large shipment of medicine was ordered deep into the Zone.
After the talk, Marked One contacts Hiko. He will advise you to delve into the X-16 laboratory while his Interpol contacts look for the deserter. He also warns you about the military squad being in the X-16 as well.
=== X-16 laboratory ===
Six soldiers will be camped out inside of the lab and are allied with the mutants living inside. Nothing too serious will be going on and none of the soldiers are carrying special information. Make your way outside to the tunnels.
=== Yantar pt. 3 ===
Two extra controllers will be wandering around the early parts of the sewage tunnels after exiting the lab. You'll see a friendly stalker on the radar in one of the branches as you advance. Find him and speak to him; it happens to be Laperouse, suffering from a psi attack. He'll give you information on Surgeon's base in Jupiter, located underground near a [ broken bridge] in the northeast section of the territory. Then he will commit suicide.
Hiko will message you with information on the decoder key, which is on a newspaper the specialist dropped in the Agroprom Underground. A photo of it will be necessary.
=== Agroprom Underground ===
Nothing out of ordinary will be waiting for you here. Advance to the [ tunnel underneath the exit to the research institute], and find the newspaper laying on the ground. Take a photograph of it, with zoom.
=== Bar pt. 2 ===
BUG WARNING: before speaking to Docent, you might want to wipe X-18 out, especially the control room. There were reports of Ustinov being killed by the local fauna.
Go to the Bar and speak to Docent; he is currently in possession of the decoder. He'll require 60,000 RU for decoding the three PDAs, promising to tell you when he's done. Meanwhile, Hiko messages you again. He has located the blocked door leading to Surgeon's underground base. He'll be scouting out X-10 for an entrance, and advises you to search for one in X-18 laboratory.
=== X-18 laboratory ===
Descend into the X-18. In the observation platform above the embryo chamber at the bottom level of the lab, you find a non-hostile karlik named Professor Ustinov. Speak to him. He has a decoder for the X-17 lab doors, but in exchange he'll want two things. This starts Access to X-17.
Return to Ustinov with his kitten and the embryo, and he'll tell you that the insane surgeon who was employed in X-17 previously was called "P-1". You'll also receive the decoder to the lab doors in Jupiter.
After the talk with Ustinov, Sakharov will call with information that the medicine shipment was picked up by a squad of ten mercenaries. Strelok will also call Hiko with all the information gathered. Hiko tells you to go ahead and try to gain entry to the lab on your own.
=== X-17 pt. 1 ===
The transition in the northeast section of the map will be free for you to enter. However, once you descend the steps into the lab, you'll take unavoidable ticks of fire damage. After an exchange with Hiko, you'll decide on getting a special suit made by Vasily to combat the artificial radiation.
=== Swamps ===
Vasily will remark that he's had to make 20 of these suits for previous customers, Laperouse and his squad, so he has the process down pat. This opens up Special Armor Suit, where you have to bring him the materials and wait for a day to pick up the Modified firefighting suit.
After speaking to Vasily, Docent will tell you what he's found on the PDAs. A secret military installation that can direct superheated radiation into precise areas was stolen and has been tracked into the Zone. Mystery of the "Photon" product will be closed.
=== X-17 ===
Enter the X-17 while wearing the Modified firefighting suit you obtained from Vasily. Travel light, as even the upgraded suit only adds +30kg of carry weight. You could also simply carry an extra rucksack to stash your additional weight at the start of the lab.
Upon entering the lab, Descent to the Underworld will begin and Hiko will tell you to switch off the radiation emitter. This quest will be marked as complete after finding Surgeon in the lab below.
== Notes ==
* Don't try to enter X-16 from Yantar until you've talked to Kuznetsov and then Sakharov. The military operation will be still ongoing and a scripted sniper shot will instantly kill you when you get close to the indoor entrance.
** Even if you do enter from Warlab, nothing special will be happening inside.
* The squad in Yantar will not be allied with zombified stalkers, and will fight inside the factory before you even arrive. Make sure to search the area thoroughly for the commander, as he can die to friendly fire or a zombified stalker in unexpected spots.
* A total of 310,000 RU is spent in this questline, not including extra costs for other materials you need for the suit. Keep this in mind if you're low on cash.
== Bugs ==
* Professor Ustinov sometimes dies to the poltergeist that naturally spawns in X-18 before you could get to him, softlocking the quest. Try wiping X-18 out before talking to Docent, then go talk to Ustinov in the empty lab.