It could just be me but is it a mansion at the end? I thought it looked like a prison which would be the logical place since that is some secure shit once you get rid of the Zombies in the place which would also likely be easy because most of them would likely be locked in cells.
Yeah, it's likely a prison. That's where they went next in the comic, and that's sure what it looked like to me on screen.
As an aside, a prison is exactly where I'd head IRL in a zombie outbreak. Well-armed, heavily fenced to keep people from walking in or out (which basically makes it zombie proof) and even if they breach barriers, it has plenty of internal defenses like heavy doors and locks with checkpoints. Also big state prisons usually have a lot of amenities like stocked medical center, gym/weight rooms, library, laundry, vehicles, fuel cache, parking, kitchen that is likely provisioned with enough non-perishables for a small group to eat off for years, enough cells for everyone to have their own cloister of rooms, sometimes industrial tools and light manufacturing facilities.
Everybody good, plenty of slaves for my robot colony?