The Coordinate Tracker in Civil 3D can be a useful way to VIEW and USE the X and Y values of your cursor location and a Z value from a surface.
To call up the Coordinate Tracker use the General pull-down, select Utilities, then select Coordinate Tracker from the flyout menu.
When it is present you can first select within it a surface from which it will display the elevation of the cursor location. You can then select the Coordinate Capture Keys (by default this is Ctrl+Shift+Z) to lock in the X,Y,Z, values.
There are also buttons that allow you to push the X,Y the Z or the X,Y,Z values as they were captured or edited versions to the command line.