'Worst Case Credible Scenario' Approach is most suited approach for safety reasons and
An analytical approach considering, As If we, are ourself exposed to that particular risk/ hazardous situation. Should be the guiding concept for a way forward I believe.
If we want to take that A/C credit for our life then;same may be considered for others.
Actually the basic Issue remains,as;Safe Escape Possibilities(If any!)exist or not?
Hope this gives a slightly varying view on your query.
Best Regards
Qalander(Chem)