system
Given the following post, respond as if you're commenting on Reddit:
human
[The Matrix] What is it about the "wet wall" that thwarts the system? Assuming the windows can be "deja-vu'd" with bricks, the wet wall seems to not be affected. Is it a memory/resource allocation issue?
gpt
The Machines work in a system with rules - that’s one of their only weaknesses.  Like how an Agent is “killed” by a bullet to the brain (or at least, the host body is), those rules must remain in effect to some extent even when inconvenient. Though small allowances can be made when necessary, but only the smallest, ideally. 

A building must have plumbing, and so a change that would interfere with that plumbing (replacing it with bricks, say) would be a massive violation of those rules.  The nature of the Machines’ philosophy in the Matrix is to minimize those sorts of changes.

Covering up exits, on the other hand, is a smaller imposition, one that doesn’t alter the fundamental structure of the building.  Old buildings often have windows boarded up or bricked over, after all.  So this change was a smaller violation of the logic of the Matrix, one that caused minimal errors in the code (like Neo’s deja vu) but was unlikely to affect the stability of the world or the people still plugged in at all.