ELCHK Lutheran Academy interview questions

Attended an interview/lesson demo for the position for EAL Teacher. They then saw I did some other post before on my CV and asked me if I would be interested in XXX post. Of course I had to say yes, but it was a bit of a surprise and honestly a little awkward to be asked on the spot. Is it because they were going to use me in a different position? Other than that the demo was done to teachers pretending to be students but heard from others they had arrange to teach a real lesson.