Organization safeguards can never be entirely effective because the decision makers cannot foresee all the possible accident scenarios. Then, contributing factors originating at many levels of the system, in combination with local triggers, open a window of opportunity in which the hazards are allowed to pass unchecked through successive weaknesses in the so called defences in depth. This is why a good organization has a continuous improvement process, and why a good continuous improvement process has frontline teams playing the key role of the last line of defence against organizational gaps, weakness or failures. The paper introduced a way of using Virtual Reality focusing on frontline teams for improving organizational safeguards. It presents a methodology build up during the Virthualis project, able to address the following questions: How to design an organization which provides frontline teams with some mental skills that would help them to recognize and, if possible, contribute to avoid situations with a high error potential? How to design an organization for managing of learning and changes based on such frontline teams contribution? This methodology addresses the way safety rules are written (integrating roles and responsibilities, procedures & risk assessment). It defines a structured approach for designing and using virtual environments... making it possible to work, in a collaborative way, for the design and the implementation of good practices during nominal situations and in case of degraded, rare and/or dangerous situations. This methodology is still in a research and development phase. It has to be tested and improved.