On the flip side of Opher's comment, I think many folks give up far too easily on others. A "do nothing", vanilla attitude towards someone who needs help, to me, is escapist (I'm not implying anyone suggested this here, though; a very subjective statement on my part, I understand).
Of course, you can only go so far before succumbing to those problems you try to solve -- something possibly implied in the story.
This teacher could possibly have done something else other than pretend to be an innocent bystander. Mind games make me tired. A wo-/man who deceives only to end up with only the option of killing is no moral compass for me.
Manuel said: "It is a beatiful illustrative tale and it is very, very old." An excellent point. The story definitely sounds great.