In the movie A Wednesday Nasruddin Shah the common man does file an FIR (first information report) for a lost wallet. Why does he do that? He was at the station to plant the bag of RDX, what could be the possible explanation to file the report? He could have planted it without getting noticed.
If you see the bomb planting scene again, the bomb needs to plant in toilet as per his plan. He just want to expose the security level of the country that a common man can break in to police station and put a bomb in their toilet. There can be two cases:
- When he enters the building, as far as I see, he was searching for the toilet but the constable ask him what he was looking for. And his sudden response was for FIR room where he found the toilet.
- He might has seen the architecture of the station and located the place to put a bomb in center of the station. Then he planned the FIR story to execute the plan. But this is much of hypothetical case.