I disabled the 3 security holograms near the vault and jumped down into the fog to grab the vault turret terminal password, but I can't find anywhere to use it. None of the available terminals will let me shut down the last force field that blocks me from getting to the vault proper. I need a good description of what I should be doing because this damn maze of twisty little passages all alike is starting to get on my nerves.

I agree, its a huge piss off. Finding the vault. Look for some walkthroughs by searching through google. I had to use one to help me get to the vault. It was a pain in the ass with those holograms. I don't understand how you can have over 30 DT with the Sierra Madre Rienforced armor, helmet and bomb collar...yet two shots from the holograms takes most of your health. Just a piss off.

There is a terminal in that room along the wall under the speaker; it's in the covered walkway there and can just be gotten to before the collar goes off. You need to read the entries therein; the second one (IIRC) will open further options that will allow you to disable the speaker and the last force field.

I figured it out. There's that terminal that lets you disable security, but says the elevator will leave. Well, I thought that meant I'd be stuck down there so I didn't try it. That's the only thing you can do though, so I tried it and got to the vault. Now to steal all the loot...