A city fight (1)

With the wall collapsed the army of death stormed the city unobstructed as it basically became a plain street fight without there being proper defensive mounts. 

A defending force could have an advantage while defending a city from ground zero but that needed them to make lots of pre-planning by setting up roadblocks and supply centres. 

They needed to backward integrate a whole lot of things for their forces to fall back only one block at a time with their every retreat being covered and every advance being backed. 

Such a robust structure needed careful planning of reinforcement centres , medical centres as well as wall mounted defensive structures , just like the elites did in Purplehaze city before the invasion of the blood merchants , however that was only possible because the elites knew that the attack was coming for months and had ample time to set such things in motion.