walking in fours
'Walking in fours' is a police technique for patrolling an extremely dangerous neighborhood on foot, and suggests a very aggressive assertion of authority. The phrase is sometimes extended to 'Walking in fours and kicking down doors', that is, breaking into people's houses to effect raids for drugs or guns, or to create a sense of terror.
'They walking in fours and kicking down doors,' said an inmate of East L.A. looking to get somewhere else in a hurry.