For those among us who are eventually less home in this particular subject (others might want to skip):
Basically, there are 15 mission tracks contained in the game folder, 3 for each "organization":
MisZion, MisMachines, MisMerovingian, MisNiobe, and Mission1.
MisNiobe was actually designed for the Zion missions controled by Anome, and although some track occasionally leaked on an Anome mission here and there, it never really worked. If they haven't fixed it for the archival missions, they're probably working on fixing it.
Mission 1, "neutral", is played in neighborhood contact and PB missions.
However, apart from the two tracks played ingame, for out of combat (marked with an "L" in the music folder, "primary"
and in combat (C for "neutral", H for the rest), there's a third track in each case (M, "secondary" which has never found a way into the game - except Machines, which is the combat music for the Zero One and One Zero archives.
Now, with the upcoming white hallways and org specific areas, there's a suggesting opportunity to do justice to these great tracks by Don Davis by implementing them as background music for these new areas. On the other hand, of course, it would give the areas a special feeling that's different from missions, and just add something to the musical variety.
It would go easy as this:
MisZionM, MisMachinesM and MisMerovingianM for the according organization areas, and Mission1M for the actual hallways.
A (probably worse) alternative to implementing them as primary music would be as combat music, if there will be enough combat in these areas. The more energetic character of the M tracks qualifies them for this, more or less, but again, I think it would be the weaker alternative.
Except that I could've written this shorter, what are your thoughts on this?
P.S: Those who'd like to listen to the M tracks, take a look in here: http://www.mxoarchive.net/music.html