Looking at the map, Yan Xiaobao knew their troops would have to split up to seize the city. Eliminating all enemies within the city would not be an easy task, especially since he needed to reach the Imperial Palace and rescue the Emperor's prisoner. Only by doing this could they win this war.
Unfortunately, Yan Xiaobao was not certain if they could storm the city easily. The Crusaders were waiting for them, along with their Saints. If one of his troops encountered a Crusader troop without their Saint, they would easily be annihilated.