Curious kid outside the police station

Writers credit and thanks to Nana for this :)

Picture this - Nana and sweaty grubby grandson with bike, who were just coming home from play park. 

Curious kid stops outside his local " not open to the public " police station with 2 police cars parked outside.

Curious kid's questions:

Where are the policemen?
What are they doing inside?
Why can't you go in?
(Now looking at the cars) How do they put the flashing lights on?

Nana by this time, and having tried her best to answer the above questions, was having visions of been spotted on their CCTV cameras, and was about to be charged with loitering!!!!