Prospective MK teachers who have degrees in subjects that do not have counterparts in schools may still pursue becoming an MK teacher. However, they may have to rely on minor fields or general education courses to form the basis for a subject to teach.
We know of one case where the prospective MK teacher had a degree in drama and applied for a position in a large MK school and got the job.
While you may have a desire to become an MK teacher and to serve the Lord in this way, you must be able to be a contributing member of a school faculty in order to be useful. Making an application to a mission agency when you do not have an acceptable content area to teach would prompt a question like, "What position do you expect to occupy in a school for children of missionaries?" You could respond with "Drama," or some other non-content area and let the school determine if they can use you or not.
While it is true that some schools have a hard time recruiting teachers, these same schools have an obligation to the children they serve and to the parents who trust the schools to teach their children. These children deserve the very best education we can give them.