Walker and many of the soldiers had split from one another. Groups of three or four to explore the ruins. They all knew that there would not be any monsters around. The undead had ensured that was a thing. Therefore, the safety was fairly high when it came to battle.
This was not the same when it came to collapse. There were some heavy battles that went on. Ventus and Ignus had been burning very high intensity flames all around. Just because they focused these flames and wind attacks on the undead, did not mean that the ruined city would not be affected.
The ruins had been tempered with flames and wind through Ignus and Ventu attacking. Therefore, they would clearly change. Some of the stones showed black marks where undead had burned next to on them. While other places showed the heat and cooling stress cracks that any stone super heated too fast or cooled too fast would have.
