I'm certain many of you know about this already, but for the people who don't, this is an insane leveling spot for 90+. As a prerequisite, you need to complete the Mayor's quests in NLC up until you need to take down the drill (quests start at level 90).
If Corridor 6 is crowded (which there is a 99% chance it will be), Corridor 5 is a decent alternative, though not as good (obviously).
This is good until about 125 or so. Happy grinding~