They were heartless, ruthless beings with no morals at all. The Turks of Shinra Inc. were what one might describe as a secret police. But they were so much more.
They were machines. Unable to disobey. Programed to kill. When one broke down another would replace it.
Their loyalty was tested constantly. Shinra Inc. itself was the real machine; they were the cogs. If they were to destroy a city and its citizens, so be it. Slaughter their mothers? An order was an order.
All machines come to a point where they are unable to resist their programmers any longer.