When using the native InRoads command under File > Export > Surface, it immediately crashes InRoads and MicroStation when you attempt to save the file.
This is a known defect with InRoads SS3 08.11.09.493 that will be fixed for the next release of the product. Insteead of using the Export Surface command you can easily use the Tools > XML Reports > Surfaces. Select the Surface you wish to export and select all features you want to include. Toggle on the option for Include Feature Points and Apply. Once the Report Browser Opens, look at the Surfaces > SurfaceInputFormat.xsl. You can highlight and copy the data to a text file to have XYZ information. Then if you need it formatted as tab delimited or CSV, you can import it into Excel and excel will use a wizard to format the data. Then save it as needed.