The Reduced to Rubble quest in Arc Raiders is a little odd. It's not actually that hard when you know what you have to do, but since your first task includes photographing a location, I immediately found myself wondering whether I needed a camera (which isn't even an item). And then you have the vague objective to "follow the trail of destruction", which isn't saying much in an area full of debris.
So you're not stumbling around aimlessly like I was, I'll go over the exact locations you need to visit to complete the Reduced to Rubble quest below.
Given you'll be sent on quite a trek through a dangerous part of the map—Olive Grove, where everyone and their mother is looking for lemons, apricots, and olives—I recommend bringing a free loadout.
How to complete Reduced to Rubble in Arc Raiders
The Reduced to Rubble quest has two main objectives (broken down into four quest steps) to complete across Blue Gate, though you don't need to do them all in a single round. You also don't need to bring any specific items in or out, so don't worry about gear. Here's what you need to do:
Photograph the Collapsed Highway
This first step is much less complicated than it sounds. Just head to the west side of Highway Collapse (north of its map marker) and you'll find the 'take photo' interaction between a tree and a rock where the highway has collapsed.
Once you've done that, you'll have to head to the Broken Earth point of interest, which is a fair walk east of the Highway Collapse.
Follow the trail of destruction through the Broken Earth and investigate the unknown ARC machines
This is undoubtedly the most confusing part of the Reduced to Rubble quest, thanks to its vagueness and how large this region is. What you need to do is head northeast up the hill towards the large scrap metal ring, halfway between Broken Earth and Ridgeline, directly east of Maintenance Bunker.
Once you reach this old Arc machine, the quest will update, and you'll have to interact with it to investigate it. Do that, and you've completed Reduced to Rubble, whether you successfully extract or not.
