Descent into the security shaft
Posted April 2nd 2006, expanded (and renamed) July 2nd 2019
Associated movies
Just past the control area in the security substation, you can walk out onto a balcony and peer down into the enormous shaft. But if you have PAL Xbox you can also get down a long way quite easily with a succession of falls! Have perfect health and an overshield for this. The overshield is needed to survive the first fall.
Note: on NTSC/PC, unfortunately MC isn't resilient enough to survive all the falling, but there's a co-op method you can use, which involves similar falling but in conjunction with repeated respawning.
Setting up with the Hunter checkpoint
To set yourself up with a handy checkpoint for making descent attempts, you can use what I'll call the Hunter checkpoint. It's triggered when both of the Hunters are dead, and unlike many checkpoints on this level it's fully delayable. So when you kill the second Hunter, just delay the checkpoint by jumping until in position on the balcony, wherever you want to be. Preferably also wait until Cortana stops talking, so you don't keep hearing her each time you revert. Incidentally, it's good to have a well charged flashlight on, because the shaft is pretty dark. Plus, it's good to be loaded with grenades, for playing around with.
Although any difficulty level can be used, I strongly recommend the higher ones because a bleeping shield will recharge faster. Your shield will be doing quite a lot of bleeping as you play about.
Descending - the basics
There are three stacks of pronged platforms sticking out of the wall, and any stack can be used for descent. There's one "straight ahead", one to the right and one to the left. Each stack has five platforms.
The overshield allows you to survive the relatively big fall to the top platform. A crouch landing seems redundant for that, but it makes sense to crouch land for the remaining falls (now your overshield is gone), to minimize shield damage. From the top platform you drop to a small shelf by the wall, then a platform, then a shelf, and so on. If your shield starts bleeping - which would typically be after fall five if you've done your crouch landings well - it's safest to wait for it to recharge before the next fall or you might lose health, but that's up to you.
From the final platform you can drop to a holed surface with a greenish tint (in the right light), which you can explore. If using the middle stack, you could instead reach the surface by dropping to a shelf then jumping across a small gap.
The bottom of the shaft is far below, and you can send grenades or rockets down for fun. A zoomed pistol can help you watch the results (plasma grenades can be seen bouncing). You can fall towards it for a closer look, but you'll die long before reaching it (see one of the pics), and the game always seems to revert before your body hits.
Incidentally, to negotiate a drop it suffices to just walk or run off your current surface. You don't need to jump off. For the initial drop you could do a jump if you want. But for the rest, you won't have your overshield any more, and jumping would result in a greater fall distance, which might cause health loss.
Speed descents
I've covered the basics of descending, but you can have excellent fun trying to get down fast in various ways, i.e. doing 'speed descents', a topic covered in BCM366 and BCM367. My convention for the timing is that it goes from when you start moving from your chosen starting place (I look at my footage and see when motion is first perceptible) to when you hit the holed surface (there's a red impact effect).
When you fall from a shelf to a platform, there are actually two thin slopes you could aim for to cushion your landing (see pic). No crouch needed. They're not easy to hit (it actually feels a bit fickle to me), but if you nail it there are two benefits: no shield damage and no motion stun (i.e. you aren't momentarily immobile). Both of those benefits are useful for doing speed descents. If you don't quite nail it, it's possible that you take shield damage but at least evade motion stun.
There are further things you can do to help, but the main one is how you start the descent (something which could be part of categorising the type of speed descent you're doing). Thanks to your overshield, your first fall can potentially take you much further than the first platform if you exploit bouncing suitably (and by 'bouncing' I mean any degree of deflection, major or minor). There are various possibilities there - some more easy than others - and you might like to have the fun of trying to find them for yourself before watching BCM366 and reading the written commentary on it which goes into detail. But the upshot is, you can end up getting down in considerably fewer than the usual ten falls!
Shelf cushion mystery
There have been times when a fall to a shelf resulted in no shield damage (normally I'd have some damage). Was that because my crouch landing was timed especially well, or is there something freaky happening? Whatever it is, I haven't been able to do it reliably. Incidentally, on NTSC/PC, falling to a shelf apparently loses you three health bars - which is at the root of why you can't make it all the way down. Tough break!
Setting up with no music and maybe a rocket launcher
With the basic set-up you'll have music playing. If you'd prefer to have no music - giving quite a different atmosphere with lots of echo - you have two options. One is to simply maintain the checkpoint delay until the music stops - which it does after several minutes. Here's the alternative option, which also gives you the chance of getting a rocket launcher.
Initially, leave one or both of the Hunters alive. Operate the control to trigger the cutscene, then return to the Hunter area and kill the newly spawned Elites. Go up the exit ramp to end the music. If you've lost health, restore it. You could also get the rocket launcher if you want (for the fun of firing it at stuff in the shaft). Get a fresh overshield then go back inside and exploit the Hunter checkpoint as before, i.e. trigger it and delay it until position for descent.
Getting a low checkpoint
If for some reason you'd like to have a checkpoint somewhere down the shaft - e.g. on the holed surface - that's no great trouble. Just keep a checkpoint delayed until you get there. Two delay causes you can exploit: falling, and having active ordnance (e.g. needles from a needler).
Warthog escapades
It's quite easy to squeeze a Warthog out onto the balcony and get a delayed checkpoint there, then have fun driving it off towards a platform stack, where interesting things can happen. It's good to have Marines along for the ride. They do a lot of amusing yelling and can end up ejected onto a platform or shelf. The hog can end up in amusing situations too, such as being embedded in a platform or resting on it precariously. There's lots of this in BCM368, which also outlines how you can set things up.
It's even possible that the hog will get you all the way to the holed surface. It's liable to take considerable luck to get enough good bounces that the hog never builds up too much speed, but I've done it a few times now, and one time (as seen in that movie) the Marines made it down too! I don't know if there's a relatively 'controlled' way to do it. I haven't tried to pursue that.
Here's another activity, covered in BCM369. You can easily blast a hog down to the holed surface. If you then delay a new checkpoint until you're down at the hog, that sets you up nicely for driving it off the surface to try and get a closer look at the bottom of the shaft. If you dismount as the hog is falling, it can slow you up a bit (either as you dismount or if you subsequently collide with it), so your eventual death occurs lower than usual. See the accompanying picture for a good close view I got just before being reverted (there's also a rocket strike). As you can see, the bottom isn't a simple flat area. What we seem to have is a raised rimmed area in the middle.
NTSC/PC single-player possibility?
I've already mentioned that on NTSC/PC, MC can't handle all the falling in the basic method. But it looks like there's still a way to reach the holed surface in single-player. I say that because Ducain's old movie 'Assorted Trick Goodies' includes footage on the holed surface (he'd even checkpointed there), and I think he was using NTSC. I don't know how he got there though. Maybe the Warthog came into it? I'm pretty sure you can get down with a hog, just like you can on PAL.
History and links
Although I arrived at the descent by my own exploration in 2006, I assume PAL players were getting down the same way long before that, though I'm not sure how widely the possibility was known. Legolas' 2002 co-op method seems to've been the first advertised descent to the holed surface (which was called the 'bottom' though it isn't really). In the relevant forum thread there were no PAL players commenting that they could do it in single-player, so perhaps it took a while for them to realise you could. There's a post around six weeks later from someone who got down solo. Was that the first time someone with PAL mentioned the possibility? Louis Wu's reply gives that impression, but I can't be sure.
My original version of this article was titled "Descent into the substation abyss" (advertised in the HBO forum here), but now that I've returned to it to expand my coverage (including movies), I've switched to using the term 'security shaft' to match older terminology. Louis Wu used that term here for example. At the same time, I've switched to using the term 'main shaft' for the shaft in the main facility.