I imagine pulling one of those blinds open and seeing that background of endless skyscrapers around your own, with no activity anywhere. Except when you briefly spy “something” in a far window, that suddenly turns and looks at you then runs out of sight. That was one of the most frightening scenes in all the Backrooms stuff.
Unless some evil god is opening a portal to a dark dimension. Movies have taught me at that point, you throw everything you can at it, from crossed beams to houses to nukes to whatever you have handy.