Choibalsan is indeed close to Russia and China. The Russian border, to the north, is 200 miles away by road. China, to the east, is less than 50 miles distant as the crow flies. Preach My Gospel says this about culture:
Culture and language are closely related. Understanding the culture will help explain why language is used the way it is. Strive to understand the culture of the people so that you can communicate the unique aspects of the message of the Restoration in a way that will be clear to them.
One of the greatest things you can do to gain people’s trust and love is to embrace their culture in appropriate ways. Many great missionaries have done so (see 1 Corinthians 9:20–23). Seek to have the people feel comfortable with you and your language.
I know that in this case the culture that the missionaries would be concerned about would be the Mongolian culture. But then the comic wouldn’t work.