Gears of War: E-Day: How to Beat the Scoria at the Refinery Core (Critical Failure)

The fight at the refinery core in Act 4, Chapter 6: Critical Failure drops you onto a circular deck around the glowing converter with a single objective on screen: “Kill the Scoria.” There are two of them, giant winged beetles that move between the air and the deck, and each carries its own thin health bar. The chapter does not end until both are dead.

Quick answer: Fire the Prototype Lancer at an airborne Scoria; when one touches down, switch to Gut-Puncher grenades and target its glowing body. Sprint sideways to evade each yellow blast, and collect all three ammo pickups around the outer ring.

Grab the Hard Case before you take the lift down

On the control deck above the vats, a Hard Case sits beside the console just before the lift. It contains Impact Rounds for the Ripper LMG mod and displays “HARD CASE EMPTIED” after you collect them. Take the contents before lowering the lift; you cannot return afterward. This route also has four of the chapter’s five collectibles, all obtainable before you descend.

Activate the lift using the control at the platform’s edge. A brief cutscene shows a large, red-armored Locust at the converter as the first Scoria arrives. Control then returns at a checkpoint. You drop in equipped with a heavy multi-barrel gun holding 147 rounds, a Prototype Lancer at 600, a Gut-Puncher at 14, a Snub at 136, and Frag Grenades.

What the Scoria do and what actually hurts

The two Scoria repeatedly alternate between flight and walking, typically leaving one airborne while its partner is on the deck. An airborne Scoria opens its wings and sends a broad shaft of white-yellow light downward. Once grounded, it takes on a wide, hunched shape, advances toward you, and unleashes the same close-range blast across the floor.

The searing yellow attack causes most of the damage and sets the deck alight where it strikes. When a Scoria takes aim and begins glowing, sprint laterally to escape the attack, then leave any burning patch of floor. A red cog-and-skull emblem at screen center signals that your health is almost depleted. Your squadmates are knocked down repeatedly during this fight; a red marker labeled with a squadmate’s name shows who needs help.

No weak-point marker appears; fire on the glow brings the health bar down.

A Hammerburst is beside the outer railing, where X displays the pickup prompt. You can do without it; machinery, crates, pylons, and railings offer no protection from a blast if you remain in its path.

The fight in order

Open on the first Scoria hovering ahead of you with the carried heavy gun. Its 147 rounds last about ten seconds, so empty it into the flyer and then drop it.

Kill the Scoria, first one hovering — Opening on the first Scoria while it hovers overhead — keep moving as you fire. Shown at 604:42 in MKIceAndFire’s video. Image: The Coalition

Equip the Prototype Lancer and fire at the airborne Scoria. When the first one descends and lands nearby, switch to the Gut-Puncher and launch grenades at it; the reticle reads AUTO / MANUAL. Move backward around the ring between shots. It retaliates with a yellow blast, so keep dodging sideways instead of stopping. The Gut-Puncher empties fast.

Take the first ammo pickup on the outer ring. It refills the Lancer and tops up the Gut-Puncher. Go back to the Lancer on the Scoria flying overhead and keep moving the whole time until the first one dies.

The second Scoria starts on the deck with its bar nearly full, before taking flight. Keep firing the Lancer until its magazine is empty while another blast sets the floor aglow, then pick up the second ammo box for a substantial Lancer refill. Use the weapon wheel to re-equip the Gut-Puncher against the grounded Scoria.

Don’t approach a grounded Scoria from the front at close range. Its low blast strikes Marcus and sends him down: the screen goes white, “DOWNS REMAINING” appears above the emblem, and an X-button icon appears beneath it. Marcus crawls for roughly half a minute before standing again. Keep your distance.

Pick up the third ammo box on the ring, then equip the Prototype Lancer again to finish the fight. The final Scoria hangs beneath the overhead girders, firing vertically downward. Keep shooting its body with the Lancer until its chest catches fire; it dies in that position.

Chest alight, final Lancer burst — The final burst — the last Scoria's chest glows under the girders as it goes down. Shown at 609:56 in MKIceAndFire’s video. Image: The Coalition

Ammo management across the fight

This long fight demands a lot of ammunition. Budget about 950 Lancer rounds, more than 20 Gut-Puncher grenades, and the heavy gun’s entire 147-round supply. The three ammo pickups sit around the outer ring, and you’ll need all of them; gather the boxes as you move rather than holding one position. Use the Adrenaline Injector more than once if necessary; its icon shows a countdown in seconds after each use.

How you know the fight is over

The objective line gets crossed out after both Scoria have been killed. When the second falls, “OBJECTIVE UPDATED” appears and a checkpoint is set; the new objective is “Escape the refinery.” A cutscene follows: red light rises from beneath the platform, Mags operates a console, yellow Imulsion floods through the core, and the squad departs aboard a train car. No enemies appear after the final Scoria and before the chapter ends. Control returns aboard the moving train, alongside the Act 5, Chapter 1 title card.