The statment of James of Mr. Jhon being a mental patient still couldn't be trusted by Mika's brain. It's not Mika's fault, rather he is not distrusting at all but it's' true that no one would believe what James said and that is the whole reason why Mika was looking at James with doubtful eyes.
"I know it's hard to believe but it's true." James pinched Mika on hand for doubting him.
"He wanted to be an actor but his parents died in front of his eyes when he was 15, that caused him mental problem where he makes a character in his head and acts like them for a period of time, today it's a doctor. Besides you heard Ms. Lawrence saying he steals her coat time to time. You know what he has acted as a doctor many times but never once has his personality was repeated."
