When faced with a threat, an animal must decide whether to freeze, reducing its chances of being noticed, or to flee to the safety of a refuge. Animals choose between these alternatives in a manner that largely depends on the context in which the threat occurs. Contextual cues include the social and spatial features of the environment, as well as the internal state of the animal. The mechanisms by which these cues are integrated to guide the animal’s choice and how that choice is implemented, from neuronal activity to muscle contraction and visceral responses, is still far from understood. To address this question we use the fruit fly, a powerful model organism that allows a truly integrative approach, whereby we study from collective behaviour all the way to detailed mechanistic account of the changes taking place in the whole organism when facing a threat.