Using of G4box in an example such as microyz

I know the G4box, is used to have the geometry of the world space. but I want to be sure that IT takes a geometry as a half dimension of the geometry such as for a box.
As an example, In microyz, if I have the full dimension of water box 640 x 280 x 25 um. Is it write, please?

G4VPhysicalVolume* DetectorConstruction::DefineVolumes()
{
 // G4double worldLength = 10 * m; origin
    

  // World dimensions
      G4double worldLengthX = 640 * um;
      G4double worldLengthY = 280 * um;
      G4double worldLengthZ = 25 * um;
G4double maxWorldExtent = std::max({worldLengthX, worldLengthY, worldLengthZ});
      G4GeometryManager::GetInstance()->SetWorldMaximumExtent(maxWorldExtent);

  G4cout << "Computed tolerance = "
         << G4GeometryTolerance::GetInstance()->GetSurfaceTolerance() / nm << " nm" << G4endl;

  // Define the world solid
  auto* worldS = new G4Box("world",  // its name
                           worldLengthX / 2, worldLengthY / 2, worldLengthZ / 2);  // its size

  // Logical volume for the world
  auto* worldLV = new G4LogicalVolume(worldS,  // its solid
                                      fpWaterMaterial,  // its material
                                      "World_LV");  // its name
    
  // Physical placement of the world
  G4VPhysicalVolume* worldPV = new G4PVPlacement(nullptr,  // no rotation
                                                 G4ThreeVector(),  // at (0,0,0)
                                                 worldLV,  // its logical volume
                                                 "World",  // its name
                                                 nullptr,  // its mother  volume
                                                 false,  // no boolean operations
                                                 0,  // copy number
                                                 false);  // checking overlaps
    
// Set user limits for the world volume
  worldLV->SetUserLimits(new G4UserLimits(fpMaxStepSize, DBL_MAX, DBL_MAX, fpTrackingCut));

  PrintParameters();

  return worldPV;  // Return the physical volume of the world
}

I am confused why you are defining such a tiny world volume. You will almost certainly have issues being extremely careful with particle sources. Is there any reason you could not just make the volume something like a box with 10 cm sides and then to place your tiny water volume in the center of it?

Because in the module of microyz, it is used only a box of water without any other volume inside it, So I did my dimension according to the code.