Is it Sathyan or Is it the sound?

In Nanban, when Satyaraj explains about his pen that is specially designed to be used in space, Sathyan gives an exaggerated cartoonish smile, and is accompanied by Harris Jeyaraj’s comic tone (Watch from 3:58) - the kind that S.A.Rajkumar plays in comedy scenes of Vikraman films. That very moment Sathyan becomes a caricature, a person who should always be laughed at. Is it because of Sathyan’s expression or is it because it is Sathyan playing the role or is it that ridiculous tone used in the background or it is the combination of all these aspects? I am just wondering what the scene without that tone in the background would have conveyed about the nature of Sathyan’s character. I cannot know for sure.