Why don't they go get food?
Or leave at all? Food shortage is such a problem that they're eating pets and exchanging wives for food. But nothing traps people in the building. Laing even continued to go to and from work (for a time, at least). The architect has a conversation with a police officer through a completely unlocked and open door. Why can no-one pop out to a supermarket? Or, for that matter, leave the violence and chaos and not return? People are even keeping their children in the building.
- I think one of the points of the film is how the most insidious and oppressive social systems are internalized. The high-rise was advertised as a model for the ideal society and everyone bought into it. For a time, it worked. Nobody really had a reason to leave the tower. The tower also seems to be very removed geographically from the rest of the city, so really everything the inhabitants have is in the tower. It was when the tower started breaking down that things spiraled out of the control, but the notion that this was ideal remained, that there is nothing better out there. Moreover, there's a practical reason to not leave too. They've all committed murder and all other grotesqueries, so they have no social standing outside of the high-rise. At the very least, in this neo-luddite society within the tower, they are free.
- Anyone can walk out at any time, but nobody wants to. The novel goes into this in more detail, but essentially, the residents have accepted the high-rise as the "real world" and a place where they are safe and need to be, while the outside is somehow wrong and dangerous. Laing himself starts out going to work daily, then sporadically for brief periods, until he finally is compelled to stay inside the high-rise in order not to miss any of the violence. It's a purely mental compulsion, a kind of mass-scale shared delusion.
- It's also implied in the film that the authorities only make a token appearance, because Royal is bribing them.
- The film also has allusions to various problems going on out in society, riots, social unrest, natural disasters. It could all just be the news making the worst out of contained situations, but it paints a picture for the insular residents that there's nothing worthwhile outside.
