A Game at the Highest Level
The crumbling of a portion of the city wall happened slow enough for plenty of people to process their unwillingness and eventually accept the truth of what was happening.
The Kingdom of Mechs was splitting into two separate pieces.
From what it looked like, the original kingdom did not stand to lose too much of itself. While the damage definitely set its growth back by a few decades, the active mech community in the Milky Way should easily be able to fix the gaps in the same amount of time.
Once the damage was repaired, the original humans should be able to move on with their lives as normal. They wouldn't even notice the absence of all of the displaced people after this time!
The situation for the red humans was much less certain. No one knew how much of its original functionality the splinter kingdom would retain. The proportion of damage was not only a lot more severe, but this rejected piece also looked a lot less strong and functional in every way!