This work presents a behavioural model based on discrete choice models (DCMs) in order to simulate decision maker behaviour during an emergency situation. The proposed model is a probabilistic exit choice model that allows understanding the heterogeneity of the different decision maker's tastes. A stated preference survey was designed and realized with a sample of decision makers in order to achieve this objective. Thus, the obtained data was used to model the optimal mixed logit model. The use of DCMs allows to know the behaviour of different decision maker types during an evacuation process. The case study highlights the importance of the influence of other decision makers on the decision-making process. This work could be used as the starting point in the development of behavioural models which could be implemented in the current tools for the simulation of emergency evacuation.