This is the constrain and limitationof Calibre RVE tool. Since you are running the DRC check on top cells, it will create a ascii file with coordinate, where this coordinate is based on top level.
Just open the result ascii file, on top of ascii file, you should able to see the top level cell name and precision which RVE use this cell name to identify the cellview to zoom. If you eip or descend edit into subcell, it will failed to zoom and require user to back to top level.
If you are using latest version of Calibre RVE, such as lv_micro.2009.4_23.21, this will be more flexible in zooming. RVE will open a new cell view when the DRC happened in subcell.
I may not answer 100% correctly, and this is what i understand. For more detail info, you may ask in Mentor forum.