Regarding the asteroid scenario. It seems to me that if you have a formal mathematical model of the laser and the asteroid then you can build a safe math oracle to solve the problem while if you want the AI to figure out physics by itself then "correct x coordinate" can be dangerous by exploiting an unintended mechanism of influence on the world.
A write up of the various ideas we've had around reduced impact AIs:
https://www.dropbox.com/s/cjt5t6ny5gwpcd8/Low_impact_S%2BB.pdf?raw=1