Iala
Better to permanently seal off the prime roots, blocking in the kitin menace and leaving them alone down there where it is damp and dark.
Because the Kitin are completely incapable of creating their own tunnels and passages. Go out and see things for yourself instead of blindly trusting your Karavan masters. If you actually looked, you'd see breaches through which Kitin have been observed to travel scattered all over Atys. Those are certainly not Homin-made.