I found the spot just to the east of the RG prisoner cage, where all the Spantis mobs are. That's right, on the other side of the map from where the EMP suppressor actually is. The coordinates that let me finish were around 6676,2524. To get the coordinates, pull up the area map and mouse over the map. The coordinates of where your mouse are will be displayed. I did the quest from Free Knights side, so this may not help if you are doing it as RG.