This article presents the assessment performed through a Monte Carlo simulation of the dependability parameters in a context of dynamic reliability. For that, the system is modelled by a stochastic hybrid automaton which has been defined formally. This stochastic hybrid automaton allows taking into account an important problem of the dynamic reliability: the different behaviours under the occurrence of events. The conflict that appears at any given time during the simulation representing the choice of one of these possible behaviours is determined by a probabilistic choice; a probability distribution is associated to each conflict. This approach is illustrated on a case-study represented by the temperature control system of an oven.