You could create a scenario based on Aristotle's own life in which either courage or ready-wittedness shows how the doctrine of the mean promotes human excellence. In 322 BC, Aristotle was accused of impiety and, finding his life in danger, fled to his family estate in Euboea. He referred to the death of Socrates almost eighty years earlier when he remarked that he would not allow the Athenians to sin twice against philosophy by killing him as well.
Aristotle did not show excessive courage as Socrates did by stubbornly refusing to escape and insisting that the Athenians carry out their death sentence. On the other hand, he did not try to placate the Athenians or beg for forgiveness, as many did when such charges were laid against them. Instead, he took a sensible middle course, swiftly and decisively placing himself beyond the reach of the Athenian state. This took courage, but was not foolishly heroic. Aristotle's statement shows that he knows his own worth. The philosopher contributed so much to human knowledge that it was clearly for the good of humanity that his life should be preserved, as well as for his own because he wanted to continue living. Of course, your scenario does not have to be directly about Aristotle, but could feature another figure whose life is valuable to others, and in whom a foolhardy excess of courage would damage other lives.