Patol Babu was supposed to act as a pedestrian and utter the word 'Oh!', when he collides with the hero. When he figured out that this was all he had to say, he was upset. He feels let down. If that was he expected from them, then why all this show. But he remembers the words of his mentor, Mr. Pakrashi, who thought him to put all his efforts even if the role was a small one. he also mentioned that one should never consider any role below one's dignity. As an artist one should aim to make the most of the opportunity.
That's it.