That reason alone will not stop Zanoba.
Zanoba will just set out with, [It is my duty to protect my country.]
In that case, if someone said to retreat during an enemy attack he would not just nod his head and listen.
Wait... If somehow the enemy is 5000, might that satisfy Zanoba?
While Fort Karon is holding out against the enemy Pax can gather more forces.
In other words, while Fort Karon is protected the country is stable.
I wonder if they are just pretending to defend the country.