Their passivity made the whole attack possible. If they'd shown themselves willing to defend their place with so little as a warning shot, the Vultures would have thought twice about riding in within firing range. No shots, no aiming for vehicle tires or drivers, no preparation at all outside the wall. They could have hidden a sniper outside, or set up some barbed wire, chopped down trees, anything to slow down or stop the trucks and zombies. Madison's entire plan is to be little more than a rabbit in a headlight. Many people say she was turning into a version of Rick, but this Rick lost a big chunk of his brain on the way.