PDA of the Monolith informer

Brother of the Shadow of the Monolith wants you to obtain five PDAs left by his snitch among the infidels, at five different locations.
* At the Bar, on the Arena roof.
* On the roof of the hangar at the Dump.
* In the closet on the third floor of the Agroprom research institute.
* Inside the boiler room at the Ironworks.
* Under the slabs at Hog's base in Dark Valley.
You must not kill anyone during this mission. You can use the Cloaking exoskeleton, but you will lose Brother of the Shadow of the Monolith's respect after doing so.
== Walkthrough ==
You need to plan the route using whatever transitions and Fast travel options you have. For example, Doctor is not hostile as he's a Trader, and can open the door to Bar for you, if you grabbed extra Strelok's stashes - which is also a very short way to grab the Bar stash because the exit point for the secret tunnel is right next to Arena.
Avoid the Freedom base entirely: being seen by them will wreck your reputation after the quest. Other Freedomers are fine, for example you can run past the Freedom checkpoint at the Radar to escape Central Pripyat.
If you choose not to use the Cloaking exoskeleton, you'll inevitably be shot at, necessitating good bullet protection in artifacts.
The locations of all five stashes are shown on the video below.
* 0:54 - Dark Valley
* 3:29 - Ironworks
* 4:58 - Agroprom
* 6:58 - Dump
* 10:15 - Bar
Note that this video shows how to do this without using any teleports. You will save yourself a lot of time using at least the route to the Bar available from the extra Strelok's stashes and a Monolith teleportation device to return to CNPP-2.
Smoke grenades are also excellent to have, since you can throw them at stalkers to make them panic and ignore you for a while without harming them.
Once you have all 5 stashes, return to Brother of the Shadow of the Monolith. He will give you the code to the third door, which is 4241, saying that your reward is behind that door. He also gives you a useful path from the Labyrinth straight to the Sarcophagus, and mentions "13 guards" and Monolith's stash from the Secret Weapon of the Monolith storyline.
Looks like it's time to return to Labyrinth and open all three doors!
== Notes ==
* Contrary to what Brother says, using the Cloaking exoskeleton doesn't incur any penalties; you may use it freely during the mission. 
== Bugs ==