ONI Alpha Site

Mission 05: ONI Alpha Site

ONI Facility: Entrance Bridge to ONI Interior

DUTCH • 2 Hrs after drop • ONI Alpha Site

With Covenant forces massing throughout the streets of New Mombasa, there is little point defending the location. Instead, a tactical withdrawal is called for, ideally with as many large explosions (that you’re at least partially responsible for) as possible. Back up from the bridge after arming it with explosives, then detonate the structure from a Watchtower. Fall back to the ONI building courtyard, where you must repel a series of Covenant waves before you retreat farther into the ONI building lobby. After holding off more Covenant inside the building, the only wise option is escaping from the building rooftop, accessed via the elevator.

DATA STREAM

Data Hive VISR Target Acquisition Mode Ratio: 10 percent*

*COMM Data Terminals are available only during Rookie missions.

Preferred Weapons

• Spartan Laser
• Sniper Rifle
• Chaingun Turret
• Gravity Hammer
• Shotgun
• Rocket Launcher*

*When handed to Mickey in the ONI Building Lobby

Par Score

• 60,000

Level-Specific Achievements

ONI Alpha Site—complete this mission to unlock “Firefight Mission: Alpha Site” Laser Blaster: Get 10 Spartan Laser kills
on ONI Alpha Site

Mission Objectives

• ONI ALPHA SITE Arm all charges on bridge
• ONI ALPHA SITE Use detonator in Watchtower
• ONI ALPHA SITE Fall back, defend inner courtyard
• ONI ALPHA SITE Retreat, defend ONI Building interior
• ONI ALPHA SITE Take elevator to roof for evac

Choke Point 1: ONI Bridge (Demolition)

Objective

• ONI ALPHA SITE Arm all charges on bridge

You’re given the order to arm all the charges on the bridge, as the Covenant are gaining ground and threaten to swamp the ONI Building in minutes. Their ground forces need to be waylaid with a spot of demolition. Each set of explosives [1A] is on a separate support pillar, clearly visible. When all three are activated, rush to the end of the bridge, where the UNSC barricades have been hastily erected. Leave the Covenant incursions (a huge group of Grunts and Brutes, plus three Wraiths) to the defenders; you have a more important responsibility: the objective that just updated.

Objective

• ONI ALPHA SITE Use detonator in Watchtower

As soon as the objective updates, turn to the left (northeast) and locate the UNSC Watchtower [1B]. Climb the ladder embedded in the structure. Once atop the Watchtower, you can take the Sniper Rifle you find there and optionally zoom in on the advancing Covenant on the bridge; there’s no point tagging them, as this simply wastes ammunition. Instead, move to the terminal and immediately power it up. This sets off the detonation program, and the Superintendent unlocks the keypad and sets off a massive explosion, completely devastating the bridge and the Covenant ground forces on it. Drop to the ground below the Watchtower. There are Health Packs and Gauss Turrets on the concrete overlooks on either side of the Watchtower, but you shouldn’t need to use either of these. Follow Mickey’s plan and tactically withdraw, heading southeast toward the massive, cube-shaped ONI Building.

Tactic: Culling the Covenant

This tactic is not recommended for those on higher difficulty levels, because one hit from a foe can make this tactic fail. At lower difficulties, however, those skilled with weaponry can easily dispatch most (if not all) of the advancing squads of Grunts and Brutes. Headshots from the barricades or Watchtower is the best plan. The only drawback is listening to Mickey yell at you to get on with arming the charges.

Tactic: Flee from the Covenant

On higher difficulty levels, Mickey’s advice is sage: You have little to no chance of repelling the Covenant squads before they overrun and kill you, unless there are four players on your team (even then, the challenge is almost insurmountable). The Covenant brings in yet another Wraith, additional Brutes and Grunts, and two Banshees. It is time to retreat....

While one of your team scales the Watchtower to detonate the explosives on the bridge, the others can access an impressive Gauss Turret on either side of the defenses [1C], and cut down the Covenant prior to the detonation. This isn’t mandatory but adds to your score. Unfortunately, you can’t detach the Gauss Cannon.

Objective

• ONI ALPHA SITE Fall back, defend inner courtyard

Choke Point 2: ONI Courtyard—Security Zone

After dashing into the courtyard, you are instantly set upon by a couple of Hunters, Brutes, and Grunts [2A] that a Phantom has dropped in. The open space and limited cover (unless you dive behind the large concrete platforms and planters on either side of the stepped area) means you are an easy target, and there are more Covenant on the way. Stand firm and tackle these foes, or, if you’re playing on a higher difficulty, flee to the top of the steps, toward the ONI Building. Retreating to this fallback position [2B] allows you to locate more cover, gain help from the local police who are holed up behind barriers in this area, and rearm yourself, as there’s a variety of scattered weapons and Grenades around the defenses. You also gain a height advantage, shooting down on the enemy. Now plan for the incoming waves—around four or five Phantom drops, each with masses of Brutes, Grunts, and Jackals to face. Jackals are a particular problem, as they feature prominently and can strike you from long range, react with sniping of your own, and move from cover to cover as the opportunity arises. There will be three Wraiths [2C] dropped at the open (northwest) end of the courtyard, and these can decimate you if you’re caught by their plasma mortar. You can tell when the last wave of foes arrives, as a Brute Chieftain [2D] appears. As soon as the next objective appears, follow Mickey’s advice and descend into the ONI Building interior.

Tactic: Close-Combat Engagement

On lower difficulties, you can take the fight to the enemy, heading down the steps and waiting for the Phantoms to drop off their cargo before charging in with guns blazing. While not subtle, this tactic allows you to quickly drop foes before they disperse and attack you from multiple angles. If you can arc a Grenade into the opening Phantom cargo doors from which the foes descend, or drop a Grenade on the ground where they all land, you can remove multiple threats with a single strike.

Tactic: Cover-to-Cover Situations

On higher difficulties, it is vitally important to remain behind cover and as high as possible along the flat paved section at the top of the steps. This allows you to snipe at foes from long range as they ascend up to you, but not at the expense of leaving yourself open to attack; the concrete planters and barricades are useful as cover. Continuous movement and “Phantom-scanning” is also helpful. Stay mobile so you aren’t outflanked, and remain at the sides of this courtyard to remain safe. Always check the skies for incoming Phantoms; they drop foes in the central, left, or right sides of the base of the courtyard steps. Knowing where the enemies have dropped in allows you to pinpoint them as they run into view.

Tactic: Turrets and Lookout Platforms

Generally, the more difficult your task is, the less time you should spend on the stepped platforms overlooking the courtyard. Although some have Turrets, you’re a prone target who can be cut down from multiple angles and by multiple foes. The Turret, however, does have its uses if you wrench it off its stand. This stops the ammunition from being infinite but does allow you to avoid incoming mortar fire. Now move along the upper pavement, cutting down multiple foes until the ammo runs out, and secure another Turret you can run around with.

Tactic: The Laser Blaster

Couple your Wraith takedowns with the Laser Blaster Achievement. Taking down all three Wraiths, one at a time once the Phantom drops them, nets you points and a quick Achievement, although the progress is hard-fought. Because there’s a chance you might miss if you fire at the Wraith from extreme range, it is better to head along either perimeter side of the courtyard to a Wraith drop-off position before heating up your Spartan Laser and demolishing it with a single strike. Don’t wait and watch the pretty explosion; enemies will already be heading to intercept. Instead, retreat back to cover, continue the fighting against the Covenant infantry, and check for more Wraiths being deposited by Phantoms to repeat this tactic.

Objective

• ONI ALPHA SITE Retreat, defend ONI Building interior

Choke Point 3: ONI Interior: Lobby

The Covenant continue to overwhelm the city defense forces, and you have no choice but to enter the ONI Building lobby. Follow Mickey, ideally giving him the Rocket Launcher so he can lay waste to the incoming Covenant and help you out with impressive kill counts. Move down the entrance corridor, then go south into the stepped lobby area. Pass the large UNSC pillar to the central lobby area [3A], where minimal sandbag defenses are augmented with a Chaingun Turret, Grenades, and SMGs. The enemies, consisting of waves of Grunts, Jackals, and Brutes, are about to appear from either of the two doorways [3B], which have energy walls that don’t allow you to head back to Choke Point 2. However, the signs, pillar, and the sides of the staircases allow you to set up sniping or ambush positions to help your cause.

Tactic: Up Close and Personal

The Turret in the middle of this lobby is the perfect piece of killing equipment; keep it on its stand so you have infinite ammunition and an easy, 90-degree turn when aiming at either of the enemy incursion points. Then let rip as soon as foes start to infiltrate the premises. This usually isn’t an issue on lower difficulties, but if you’re being struck by enemies, wrench the Turret off its stand and become mobile with it. Remember, you have Mickey and the police on your side, so don’t expect to lay waste to the entire incursion yourself. You can follow up combat with a Shotgun, stepping around corners to blast foes before heading around cover to blast again.

Tactic: Far Away and Impersonal

On higher difficulties, it becomes more problematic to wield the Turret without being injured, as you’re slow and almost always compromised if you keep the Turret attached to its stand. Instead of employing the Turret (which can still be effective), if you have a Sniper Rifle (or any ranged weapon), you can stay behind cover, even heading up the stairs to the southeast to gain extra defense from more sandbags and additional height. Tag foes with headshots as they appear, and move from cover-to-cover opportunities if you’re in danger.

Tactic: Up Close and Enraged

If you have a more aggressive attitude at higher difficulties, correct positioning and aiming is crucial. When you hear Mickey mention an incoming enemy wave, run with your Gravity Hammer (sometimes secured from the Brute Chieftain in the previous choke point) at the ready, toward the base of the energy walls blocking your path, and wait for the enemies to start streaming out. Lob a Grenade in there so it catches multiple foes, ambushing them when they are grouped together before they have an opportunity to spread out. Continue this tactic until you’re out of Grenades, or the foes manage to struggle through your projectile bombardment; then finish them with the Hammer or Shotgun.

After a few waves of foes emerge from the doors, the action ceases, allowing you to regroup in the central area and rearm. There is the usual assortment of Covenant gear to take, too. Then be ready for a Phantom to drop off several Brutes and Jackals from the exterior platforms to the south. These foes usually infiltrate the upper lobby area [3C], but the numerous pillars provide many cover opportunities. Choose any of the previous tactics to nullify the threats. Remember that if you’re fast enough, you can lob a Grenade at the ground where the foes drop to from the Phantom, on the outside platform, severely impeding the enemy forces.
As soon as you’ve slain the last of the enemies, the elevator near the central lobby area becomes operational; access the door and you receive a new objective. Step into the elevator and activate the terminal inside. The elevator ascends to the ONI Building’s roof access.

Objective

• ONI ALPHA SITE Take elevator to roof for evac

Choke Point 4: ONI Interior—Elevator and Escape

As you ascend in the elevator, flick on your VISR Enhanced Vision, and arm yourself for combat with Drones; a swarm heads up from underneath the rising elevator [4A] and flits about, annoying you and your team. You can optionally tag each of them using your skill, or simply cower behind the elevator door, crouching until you reach the top of the shaft, where the Drones are no longer a threat. This saves ammunition, at the expense of points and pride. When you reach the roof access, follow the floor markings, passing a Health Pack, and move outside.

A Police Pelican will eventually meet the team on the pad outside, but the landing zone (“LZ” in-game) isn’t safe yet; there are Jackals and Brutes to wipe off the rooftop before you can be extracted. Face off with Jump-Pack Brutes, Brutes, Grunts, and Jackals [4B]. Remember that you can duck back into the roof-access corridor if you need to rest and regain Stamina. Otherwise, a series of sniped takedowns is always appropriate. On lower difficulties, wading in with a close-assault weapon (like the Shotgun or Brute Shot) can quickly clear the area. There aren’t enough enemies to make this a particularly harrowing escape, and you can always load Mickey up with your favorite weapon and watch him rampage through the foes. You can even take the Turret from Choke Point 3 with you if you wish. A few moments later, with the remnants of your foes still active, the Pelican hovers on the pad [4C]; extricate yourself as soon as you wish. Your team has prepared a special surprise for the Covenant forces still inside the ONI Building.