Asimov's Three laws of robotics is busted. Not only can they never protect us. Even if the robot was forced to comply it wouldn't be able to move. This considers of coarse the robots ability to comprehend the laws.
Well the laws were meant to put restrictions on the robots actions. The laws as written would cause the robot to seize up. The laws are busted, Not only in science but also in their intent.
Using the 3 Laws of Robotics in a story as intended is NOT science fiction - Its Fantasy.