Down the Walls, where the breach was located, tens of Monstrous Spiders and some Ettercaps had already managed to get past the defensive walls and enter the City. Unfortunately for them, they were met with fierce resistance from the Silvermoon Knight recruited, who were already stationed there in defensive formation.
Each time a Monstrous Spiders approached them, they would be cut down by the sharp elven blades almost immediately, not even taking several seconds, unfortunately for them, they were Steel-Tier Knights, and their stamina was finite.
So after some time, they would start showing the first signs of fatigue and would be overwhelmed by almost inexhaustible seeming hordes of Monstrous Spiders and other stuff, which was now just coming through the breach in the walls.