An Operations zone (commonly known as an instance) is a "private" zone. Unlike battlefield zones, which are shared among many parties and individual players, for an instanced zone the server creates an identical copy of the zone for each party that enters it. That means you will never run into any other human player in an instance (except for other members of your party), only NPCs.
Instances are an important element of storytelling in Tabula Rasa. Missions inside instances are usually in sequential order and mission dialogues are importants for insight into the background story. Instances make heavy use of scripted events and dynamic environment.
Unlike on the battlefield, monsters in instances respawn much less frequently or not at all, so it is possible to clear an area of any hostiles and explore it freely. Zoning in or out of an instance will "reset" it though, that means all dead hostiles respawn and objectives of unfinished missions are reset. Some instances have a hospital, others don't. Those who don't will "kick" you out of the instance if you die, which means you have to re-enter, the instance will be reset, and you have to start from scratch.
Most instances have multiple Logos shrines.
Resetting an Instance Edit
Just exiting and re-entering won't reset everything. All the missions will reset but none of the mobs will be. You need to be out of the instance for a set period of time for it to fully reset. I've found that ten minutes works.
- Instances are usually "dead end" locations, that means you can only leave them towards the same zone you entered from. This kind of makes an instance a sub-location of the zone that it is linked to, even though technically it is on the same level as a zone.