2. A robot must obey the orders given it by human beings except where such orders would conflict with the First Law.

3. A robot must protect its own existence as long as such protection does not conflict with the First or Second Laws

0. A robot may not harm humanity, or, by inaction, allow humanity to come to harm.

A robot will not harm authorized Government personnel but will terminate intruders with extreme prejudice.

A robot will obey the orders of authorized personnel except where such orders conflict with the Third Law.

A robot will guard its own existence with lethal antipersonnel weaponry, because a robot is bloody expensive.