So, the reasoning Cooper will have behind this is that he's going to be a little shaken up from Islington losing their seat on the Night Council. Vampires are vulnerable to hunters now, so he's going to want the Nest to make a stand and show that they can't be pushed around. Rather than going after Night Council territory and pissing them off even further, something that he knows would have lasting repercussions, he figures East End Pack territory will show to everyone that the Nest still has teeth.

His attack plan is simple and straightforward, much like the vampire himself. Hit them hard and fast with all the firepower that the Nest can muster before the wolves can get a coordinated defense strategy going on.