I was near the end on floor 6, I had a long long way to go to the exit. Carrying the crystal I was about 3 rooms away from the exit when my heroes just didn't want to move anymore. I gave the command but they just stood there. I'm guessing the massive level was just overloaded with monsters. Since I got wiped out in about 3 seconds after they stopped moving I unfortunately don't have a save file anymore (yay roguelikes!) but I do have the diagnostics and the output log. Game version is 0.5.1.