How long did you wait? The BF dungeons are generated the first time you enter, so this can take awhile.
Because the Battlefields are randomly generated, it should take quite some time. It took arround 5-6 minutes here.
After you'll see the size of the map and what's beneath it, you'll understand.
Remember, friend, patience is a virtue <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />.