So be it, however they should recognize that they are “On their own”. No troops should risk themselves, or their unit, to go looking for someone delusional enough to go preach uninvited in a war zone. If said missionaies go in, they are subject to the laws of the country they are in, and subject to capture by the enemy. They are not uniformed soldiers and do not enjoy the protections of the Geneva Convention.
Believe me, the missionaries who I know personally understand that and will not be asking any nation's soldiers to put their lives at risk to save theirs in the event they are ever captured and held for ransom or prisoner exchange, as in this case. Also, missionaries of Jesus Christ are never "on their own" in a hostile situation no matter how isolated and helpless they may seem to be. The last phrase of Jesus' Great Commission is "and lo, I am with you always". Who could ask for anything more than the ever present and intimate companionship of the great God who made the universe and all that is in it? And furthermore, obeying the orders of Jesus Christ to go into all the world and preach the gospel is certainly not an indication that a Christian is delusional. It's simply an indication that he or she is acting in obedience to the commands of God and His Son Jesus Christ, and nothing makes more practical sense than that to any bible believing Christian.
As a Brit you should be aware of the predominantly British missionaries who first took the gospel message to the pagan regions of the Empire during the 18th, 19th, and early 20th centuries. Those men sacrificed the security and comfort of their lives in Britain and the company of their wives and families in order to evangelize the difficult and dangerous regions of the world. Their examples of uncompromising faithfulness to the Great Commission served to inspire hundreds or perhaps thousands of American, Scandinavian, German and other European Christians to follow them into the foreign mission fields of the world. But in today's world, both the US and the UK must say that to our shame those same nations our countrymen and women once evangelized are now finding it necessary to send missionaries to our own nations.
I don't personally know any Korean Christian missionaries, but going by their reputation for possessing a zeal for preaching the gospel and a willingness to suffer persecution in the process of carrying out the commission to go into all the world and preach the gospel of salvation by grace through faith In Jesus Christ to all people of EVERY tribe and language (yes, Islamic Afghans too), I have very little doubt that they are of the same mind on the matter of rescue by coalition armed forces as the American and British missionaries who I do know.
A very dear missionary friend is now in Cuba attempting to get permission for several young Cuban Christians to attend the bible college that his mission board operates in another Latin American nation. Although Cuba seems to have moderated it's hostility to Christianity in recent years, thousands of both evangelical and Catholic Christians have suffered severe persecution in Cuba, including torture and execution, over the course of the last 5 decades, and there is still the possibility that my friend could be held captive by the communist regime for the "crime" of proselytizing in Fidel's communist "paradise". In the unlikely event that something like that should happen, I can assure you without any reservation that he will not be sending out pleas to the US government to secure his rescue by force of arms. By diplomatic means perhaps, but certainly not rescue at the risk of any American's life or limb.
I agree with you. I know that I don’t expect my or any government to come to my rescue. I keep an escape plan up to date and a bag half-packed if I and my family need to skaddadle. On 911, my husband and I discussed what would happen if we became civilian prisoners in a war.