In today's terrorism-prone world (see, for example, Nature 528, 7–8; 2015 and Nature 528, 20–21; 2015), it is becoming increasingly important to ensure that buildings are designed to be speedily evacuated in an emergency.

Evacuation modelling is a relatively new field that uses computational tools to predict human behaviour in a stricken building. Algorithms represent the range of people's possible reactions in the event of such a disaster (see, for example, E. D. Kuligowski et al. US National Institute of Standards and Technology Technical Note 1680; 2010). Models provide information on optimal evacuation strategies and allow buildings to be tested using real and hypothetical evacuation scenarios.

Making evacuation modelling mandatory in the design and assessment of existing and planned buildings that could be at risk would minimize the impact of attacks on occupants.