Apart from Sofia, Bill, and the unnamed girl who had been following Sofia, there were five men, including Bobby and Blake, along with two black teenage boys. The rest of the group consisted of girls, women, and the elderly, sick, and disabled. There was also a young couple in the corner who seemed indifferent, not saying much.
In this post-apocalyptic world, the majority of women, girls, and the elderly, sick, and disabled were unlikely to survive without the protection of the strong. Even if they managed to survive, they would likely become subordinates of the strong, living a life worse than pigs and dogs.
After listening for a while, Seth had deduced that Sofia and her husband had established this refuge on the rooftop after the apocalypse, providing shelter and selflessly sharing the food they found in the mall. It was because of Sofia and her husband's selfless protection that these weaker individuals could continue to survive safely.