Post-Mortem Interval Guide

A text guide for getting the Post-Mortem Interval achievement, complete with screenshots of every important step. Also includes some other achievements you can pick up along the way.

General Information and Important Notes

This achievement requires you to find and interact with 7 dead scientists found throughout Chapter 16, Gonarch's Lair. None of them are particularly out of the way or hidden, save for the last one which requires some setup to find.

To begin, you will need to locate the cyanogen canister in the previous chapter, Xen. You can find this near the beginning of the chapter, in the headcrab-infested research station.

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In here you will also find the welcome mat that you can interact with to get the Following the Rules achievement.

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The canister itself will be on the table in the room with the crawling zombie, after you've powered up and opened the door.

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Once you get the canister you need to carry it through the rest of the chapter, as well as the beginning of the next.

After your first encounter with the Gonarch and falling down the hole, you will need to blow up a wall:

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Once on the other side, you will find a teleporter that you can only activate if you have the canister with you. Activating it will teleport the canister to and unlock the secret room at the end of the chapter that is necessary to complete the achievement.

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Important notes:

After finding bodies 2 through 7 I had to reload a save from the beginning of the chapter to get the first one, which didn't register the first time around. This unlocked the achievement for me, so I believe that you can find the bodies on separate playthroughs. However, I can't say for certain.

Interacting with the body can be a bit tricky. Be sure to pick up any items that are next to them, crouch down and press E (or whatever you have your interact key set to) a few times.

Make sure that you've interacted with the body before you move on to the next one in order to avoid missing one by accident and having to redo everything from the beginning. You can do this by checking the achievement progress in the menu:

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If the count hasn't increased by one, keep trying to interact with the body. It should register after some persistence.

Locations

Body #1

This first body can be easy to miss. After the section where the Gonarch spits acid from you from a cliff, you will find yourself in a cave.

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After fighting off a Bullsquid, go to the left and you will find the body between some orange crystals.

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Note that this body in particular was problematic for me as I've mentioned, so do keep an eye out on the achievement progress in the menu.

Body #2

The second body is hard to miss, as it's in the cave where you have to fight off the Gonarch's headcrab babies until an explosion lets you move on.

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Body #3

As the Gonarch chases you in the crystal caves, you will need to complete a jumping puzzle to get to a detonator. The third body can be found next to it, hard to miss.

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Body #4

When the Gonarch causes a cave in, you will need to go left in order to progress further. The fourth body will be stuck in some webs blocking your way.

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Body #5

Right before the beginning of a chase scene, you might notice a red light blinking from one of the rocks on the left side (didn't capture the light on the screenshot):

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A secret path will open up right as the Gonarch appears, which will allow you to get behind it and also reveals the body.

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Body #6

Another hard to miss one, as the Gonarch appears once more you will have to set some webs on fire, the body is located right where you need to go.

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Body #7

If you've done the canister setup, you will be able to find a passage on the left wall during the final chase sequence, a bit before the boss arena. (This passage also contains a protozoan required for the Prolific Popper achievement, so if you're haven't done it yet, don't forget to kill it.)

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You will be able to find the canister in the room it leads to, and if you haven't yet you can unlock the achievements The Plan and Unquestionably Ethical, by either inserting the canister into the machine and turning it on, or leaving via the jumping puzzle and sparing the Gonarch altogether respectively.

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Either way, in the end you'll have to leave by jumping across the ledges on the left side, where you will find the last body impaled on some thorns. You can interact with this one from the ledge, even though it seems quite far away.

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If you've done everything correctly, the achievement should now pop up. Congratulations!



I hope that this guide was helpful, and thank you for reading!
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[Toast Malone]

Good Guide. I've always wondered though, how does teleporting the Cyanogen open the secret passage? Is there another person or team assisting us through Xen? It doesn't make sense to be a new team since even if you don't bring the Cyanogen the station is still set up although unreachable. Just weird point I've noticed

[OTVAL]

Nice guide.
Though, see, there's problem by design.
You find similar bodies in "Xen" chapter, but interacting with them gives you no progress towards the achievement, so player can't really tell what bodies really count and tends to skip most of them. I really don't know what i'd had to do if not for guides. Game is fine, but rough around the edges.

[Ruffle]

Thank you very much! :) it worked!

[h0x]

me personally am a fan of good old text guides, thank you mate

[Conzp1racy]

Thank you for your great guide.

[Mattia Sbinotto]

Great guide, thank you for posting! Fortunately all the bodies activated correctly for me, so I didn't have to redo any of it

[ShugoTheRipper]

Good stuff, found all the bodies except the one at the end; but for some reason I only had 2/7 counted.

Console command to spawn the canister for the teleporter (Yes it works I tested):
prop_physics_create props_questionableethics\qe_gas_cylinder.mdl; ent_setname gas

Re-running it made it "work"

[smallHead]

I ran through all of it, sat up until 2am to do it, then went too far at the end into the Gonarch boss fight and didn't have an autosave or quicksave from before the fight to go back to. These types of achievements are such a blast...

[mihailgreen]

Just press E/Use on each corpse. This is very important. This is the reason why so many people can't do this achievement. I just finally got it done myself. There is no bug.

[Tomfoolery]

I sitll can't