This can be gained on DOOM E3M1
- For this one you need to crush a dead body in a door, not a live enemy
- You should gain this one naturally as you play, but otherwise start the mission
- Press the pink eye/skin button and kill the enemy when the platform raises
- Use the left skull button at the side of the door to open the door
- Go through the door and follow the passage left to grab the shotgun
- After grabbing the shotgun use the far left side to come back around and out of the lava
- Now go back and take the other passage which was on the right before grabbing the shotgun
- Open the door and you will see 3 enemies, let them come to the door and shoot them so their body lays on the line of the door
- The door will close on their corpse and you will gain this achievement
If you need more help with this you can follow my video guide below which starts at this achievement: