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.
