FWIW, before any nuclear weapons had ever been tested, a risk was identified that the first one might trigger a self-sustaining reaction in atmospheric nitrogen and destroy the entire planet.

Faced with such a scenario, is the prudent next move:

a) blow one up and see what happens, or

b) do whatever you can to be sure it won't happen before conducting the first test, and make sure the confidence in the calculation is very very high

because I vote for b, and so did Teller.