Patrolling

An individual or group, the Patrol moves through and examines a Ground in order to ensure that it is in a generally Desired_state_of_affairs, particularly that it is safe and contains no dangerous Unwanted_entity. Rather than moving through the Ground, the Patrol may simply move such that all the (relevant portions of) Ground can be observed and checked. Detective Jones patrolled the northern half of the building. Security guards patrolled for intruders while the game was in progress.