Sure, the main corridor is from Fantasy Arc which produces the bug hunt corridor. This was a kickstarter a couple of years back that more or less came out on time. It is plywood, not MDF which I spray painted, added a little detail and glued together. It fits well and was easy to do. He now has a store online which you can find here;
http://www.fantasyarc.com/As asked by sgt Scream, the one octagon room is an old Forgeworld's Anphelion base, it has two rooms with roofs and a small corridor. It just happened to fit well with the other corridor. I've had it for many years, but pulled it out when I started setting up for mission 1. Finally, the vents are just regular plastic sheet I cut to fit the corridor. I made one piece fit inside another so I could slide them in and out to fit. It also allowed me to have 60 degree angle at one end to fit the hallways and a flat end to place against the rooms.
The furniture is a collect from many places, some forge world stuff, but some great stuff is available from Spartan scenic. I got mine from miniature market here;
http://www.miniaturemarket.com/table-to ... enics.htmlHope that helps