The ground level of the base will look like this (apologies for the ugly screenshot taken from one of my development tools):
Six barracks where most of the soldiers live in and a massive building that will have several floors. The amount of floors will be randomized but it's going to be between 4 and 6. The layout for this specific map isn't procedurally generated, it's based on a text file with a specific syntax that will be explained on the wiki shortly after the release date. It's the same concept as for the roads, crossroads and so on. The game engine randomly take a definition file from those available, making the whole thing highly moddable without coding knowledge.
The following might be considered as a small spoiler for those who care about these kind of things.
NPC's and Military Faction
Standard soldiers will patrol the ground level and attack anyone who tries to enter the base. They will run a job that's similar to guards and policemen except that it will attack anyone who enter their turf without being a friend or from the same faction. However you may find soldiers outside the military base buying stuff or having a snack and those won't be hostile toward you.
Soldiers have their own hardcoded faction (like the cops or the zombies). This faction is a police type one, if you are committing a crime in front of them, they will attack you and your wanted level will go up accordingly. However it doesn't "invade/liberate" sectors like the gangs or the police do.
The Base Itself
Like I said earlier, the entrance / ground level is mostly based on the content of a file. All the furniture is still procedurally generated (using data from the modding menu). A stair leads to the real heart of the "dungeon". The next levels will be kinda special and will introduce a lot of new stuff (at least for those who have followed this blog from the beginning).
Each level will be a relatively large area with different rooms and stuff. Soldiers in those levels will be generated only for those level, they do not take part in the city simulator, and they do respawn very very slowly. They do not have a food/fun/whatever meter that force them to go outside, they just guard the place. I do know it's breaking the city simulator stuff but at some point I have to choose between making an artificial life project and making a game ^^. Stairs from a level to another will be placed in such a fashion that you have to travel through most of the building to use them. All containers will be locked and have an alarm. The farther you go, the stronger will be your opponents and the harder will be the locks.
On the last level, you'll have to face a military commander with high-end stats, gear and minions. On death it will spawn an unique loot (weapon/armor) that you cannot buy/find anywhere else.
Playing the thing
Let's be honest, this initial dungeon won't be balanced at all. It will be designed to be ridiculously unfair. To be able to succeed, the player will need a massive amount of med-kits, a very good gear, and some luck. Also, understanding that the ground level soldiers mostly act as normal citizen may facilitate your task getting into the dungeon itself.
Coding / Modding
Dungeons like this military base will introduce a lot of new concepts (for the modders) and challenges (for the coder, me). First and foremost, dividing a level/building into several rooms, while relatively easy coding-wise causes some issue with the location of the furniture (that's a word i keep using without really knowing how to do so correctly in English). For the time being, furniture will still be randomly spawned across the area, however I will have to seriously think about defining room content in the building/zone editors in a near future. Technically speaking, dividing each floor of a building into several zones that can contain a specific set of furniture isn't especially hard. However, mixing that with other parameters like the size of the said building, the moddability and the the current AI and path-finding code make things much harder.
A new (optionally) invisible "furniture" / object will also appear into the modding tool. This is the "npc/hostile/whatever" spawning point. As the name says it will spawn specific (arrays of) NPC according to parameters. This item will mainly be used to spawn enemies into dungeons.
Various modding editors will have a few new options and check-boxes to accommodate with dungeon related changes.