The Fly was writhing in pain from having his core destroyed and he would have been screaming at the top of his lungs if Leona had not had his mouth bound with the vines as he was being dragged in a cocoon of vines.
They found an abandoned building that was involved in some sort of explosion because the walls were all black and charred. In poor areas abandoned buildings were common. It was expensive to hire people to replace entire buildings when they were destroyed during a fight, so those that owned the land where a building was destroyed would only replace the damaged building once, they were sure there was a demand for housing in that area.
This building was a few miles away from the base that they just destroyed, and it was much worse off than the neighborhood that they just left. Lining the decrepit streets that had not been repaired even though they were severely damaged with large potholes and other damage from battles happening here.