The police said they did random "vertical patrols" through the building.

Transit Security Officers can be found making random patrols of the exchange and conducting Fare Inspections on board buses.

North Vancouver RCMP also make random patrols of the exchange.

And his espersense would warn them of any random patrols.

If so, their only real danger lay in running into a random patrol.

They have also conducted random patrols of the grounds.

Mr. Foley, the assassinated diplomat, was protected by a standard system of random patrols that Western missions here had considered adequate.

For what seemed the dozenth time, he stepped out of the way of one of the SPR robots on random patrol.

At a guess, one of the sentries on random patrol takes up a post in the hall.

The ordnance bunker system was fully automated, but the sprawling base covered several hundred acres, and there were random motorized patrols on a twenty-four-hour basis.