If the DAC’s job is, perhaps, to enable command, control, communication, cooperation, collaboration, and intelligence for citywide major incidents, does this service need to be tied to a specific room or facility?
No, and there’s no need to.
When you decouple the DAC’s job from the DAC’s physical location, you can design new operations.
On the design side, for example, the DAC could be configured like a video conference call, letting your team assemble in any room with enough power and bandwidth. This would be great when the primary room is unavailable, especially in a disaster.
You could run the DAC out of a mobile command post, letting the DAC team move to a more advantageous site during an event.
You might decentralize the DAC, letting the participants stream all the resources of the DAC and coordinate with the other participants from anywhere with Internet connectivity, on any device with a screen. From mobile phone to smart television, from office desk phone to police car tablet, being present could be as easy as joining a Google Hangout. Decentralization would lower the profile of the DAC as an intentional target.
The DAC does the same job in each of these architectures. The DAC is still the DAC, independent of a how or where the team works.