Imagine you are in a half delirious state; trapped, injured and stunned from the building that collapsed around you.
The earthquake hit without warning. It's hard to say how long you were unconscious, but once you came to, you spent the first hour screaming for help. After no response, you struggle in vain with your one free arm to writhe yourself from the debris that has you pinned.
Time passes eternally as you fall in and out of consciousness.
A small amount of light passes through the rubble piled around you. You hear something moving nearby, but your mind can only fear the worst. Is it an aftershock? No, the noise is to small and localized. Is the structure going to collapse further? No, the noise persists too consistently. "Is someone there?", you shout. No answer.
It's getting closer.
Your eyes strain in the darkness trying to see into the crevice where the sound is originating.
The sound is even closer now.
You see some debris moving, and then, you scream in horror as THIS slithers through the crack:
The robotic snake swings it's head in your direction as it senses your frantic struggles in the debris and freezes it's gaze on you in recognition of your screams....
Now tell me, how do you feel in this moment? Is this a rescue, or a nightmare?
Don't get me wrong, I'd rather be found sooner than later. But what good is being found if you die from a heart attack.
After I wrote this I found an excellent Q&A with researchers who are wrestling with exactly this kind of situation. Unfortunately, their solution introduces a host of even more terrifying scenarios - teaching robots to be deceptive (which is horribly ironic because of the already strong association with snakes and deception).