Best place is to stand inside the nuclear reactor chimney somewhere in the southern area of Acter Industrial Park. Go inside that. There's only one way in (Not counting the open chimney, but the cops won't come from there). If you've loaded up on weapons (REMEMBER TO BRING MOLOTOVS), it's great. Sometimes they're almost in, but blindfire and everyone dies. Throw some molotovs outside. The bodies will burn for a long time, because the jerks run into the fire to get to you.