I know next to nothing about demons and I don’t want to, except for the little I have read (most of which is 19th century source and before), but demons don’t usually act like a snowflake who thinks he can intimidate someone escallating erratic behavior and making voices. That’s a little too much 1970’s horror film and not enough actual sinister.
Perhaps movies and 19th century literature are somewhat unreliable sources for describing how a demon-possessed individual might behave. Assuming that one believes in such things of course.