What was the point of all the police scenes???

Amazing movie, but every time I watch it, I always wonder what the hell is the point of when it keeps cutting to the police station and the useless banter between the police officers. It adds absolutely nothing to the story and honestly if you took all of those scenes out if would not change a thing to the story, and in fact would make the pacing even that much better. They show up at the end and do not even interact with any of the lead actors, just have their police cruisers run over by a tank...

The only thing I can think of is they werent in the original cut of the movie, and for some reason, maybe to give it a longer running time and to pad it out, they shot those scenes afterward and intercut them into the movie to make it a bit longer???

I just can't figure it out because it makes no sense other than a waste of time and/or a bathroom break.