The Maw/Walkthrough

Warning: Hitchhickers May Be Escaping Convicts
As soon as the elevator stops, rush for any Warthog, your choice as to which. Stick to one you can quickly get into and drive out, and try to stick to the same one every run for practice. The one immediately to the right has a small tunnel conveniently leading to the driver seat. If doing Co-op, having the second person go in the passenger seat is preferred, as one in the turret will actually change the balance of the jeep and change the physics of jumps.

Note that it is possible with one in the turret (the gunner also gives more protection from enemies) but many of the fine details are based on a single player (or driver/passenger) run.

On the first hill going up, careful to evade the plasma grenade the elite throws as it will kill, if not tip, the Warthog. Go down through the tunnel, around the triangular ramp, and charge up the ramp behind it. Watch out for the carrier forms.

At the 1.5 km mark there is another large tunnel with a large drop followed by a large climb that takes you to the next section.

The next part features Flood and Sentinels fighting. Swerve to either direction to avoid them, and proceed through the left or right corridors at the sides. Then, go through an S-bended corridor, where there are a few ramps, Sentinels, and many infection forms. Taking the shortcut in the wall is only recommended if you are driving along the opposite wall at the time since the turning circle of the Warthog is fairly large.

The next section can either be done through the center, or along the sides, both methods work. After this, the fourth room features a tunnel immediately followed by a ramp. Taking the ramp will often cause a fall, forcing you to either sidestep and drive around, or swerve between the pillars. After this room, Cortana will implore Echo 419 to extract.

One final ramp, through a room and a doorway, and the "extraction point" is reached.

If you want to watch, go ahead, it'll give you a checkpoint if knowledge of the second part of the run is too shaky. Otherwise continue. You have a little leeway (10 seconds, perhaps) as past a certain point, the audio will be cut off and the timer will start regardless.

Then there is a drop down, but instead of a climb back up as normal, there is a pillar. Avoid it and drive on the left or right over some grates.

There is a second climbless drop here, and an S-bend hallway. If taking the shortcut, you can get out, make a right, and find the Thirsty Grunt.

Make a right after the shortcut (in case the Thirsty Grunt made you forget) and continue down. After a smooth stretch, up comes the ravine. Go at top speed, but if you just go forward the whole time, on higher difficulties you will die from fall damage. Here are alternative ways:

1. Ease up on the acceleration once you are in the air, this will stop you from tipping. 2. Go out of the side, land on the wall, and grenade the Warthog back into the tunnel. 3. Same as 2, but for safety, bail out about 10 feet in the air.

There is one more drop, another corridor, and a final tunnel into which you drop. Get out as some crates block your way and leave the Warthog to its death on the Autumn. Alternatively you can double plasma grenade the Warthog out and continue (note it would be a good idea to shoot a rocket at the gunner about 30 meters up on the left wall).

Run through the flood, or if you moved the Warthog down, go up the ramp, back to the crate area, and up the ramp. Jump there, and the final cutscene should trigger.