envirnment for 3d VR unity game

Scenario for Lasertag VR game. The setting must be 9 meters by 6 meters large. it can be, for example, an industrial warehouse. you have to build a 3x2 meter setting (central as in the diagram) where multiplayer players will move and repair themselves (where there will be barriers, iron barrels, etc ...) and the other part always made up of stairs, hiding places where the enemies will come out to shoot. Scifi scenario for example