I thought the kill phrase was "divide by zero" or "Can God make a sandwich so big even he couldn't finish it?"
Actually the second phrase would work better. If you tell a robot to divide by zero it knows it's a trick. But the God's sandwich question would make it hard for them to do anything, as they will have to contemplate God, biblical references and a butt load of other stuff.
Ah, but that would depend on the programmer. If this "exception" is unhandled, it may cause a fatal error, which may cause an OS crash (unlikely) or an OS reboot (more likely). The delay would give you enough time to put a few bullets/rounds into it. No knife attacks, though, unless in the base of the "skull"... You see it messes up their aiming circuits and...um...Ah, heck with it! Fire at will!
I've always been fascinated with computers and robots - my first computer was a Sinclair ZX-80 kit (unfortunately, already assembled). However, I had a fear of anything more human than C3PO up until high school, until I did a report on robots.
In my resources, I saw real and sci-fi robots, and mentions of feelings (emotions) and bravery (in battle). At that point, you see robots as just another being just trying to make it through life, and responsible cybernetics being a way to help seriously injured people to live normal lives. If you have a heart, you put away your fears and just accept it...
Sharp, robot's can die in the drop of a pin. Part wear/defects (even lithium ion battery packs). Plus sun spots, cosmic radiation, irregularities in the magnetosphere, etc. Some of the causes of robots going rogue in sci-fi could also potentially cause permanent failure (ex. Short Circuit - No. 5 - lightning).
Just tell teach them it's "no malfunction", they're "alive", they "need input", and "disassembling" is wrong... :-)
As far as us being overlords of technology, did anyone read Asimov's "Last Question"? Interesting take on the idea...
Oh, and as for aliens, I'd suppose they'd throw a collar and leash on me, place food and water bowls in front of me, hand the leash to the cat, and head out. Just kidding... I'm sure they'll say how impressed they are with broadcast Earth tunes. (However, no iTunes, or we're talking interstellar war...)