Due to real world physical constraints (e.g. walls), experimenting a virtual reality phenomenon implies transitional issues from one virtual environment (VE) to another. This paper proposes an experiment which studies the relevance of smooth and imperceptible transitions from a familiar and pleasurable virtual environment to a similar workplace as a mean to avoid traumatic experiences in VR for trainees. Specifically, the hereby work assumes that the user conciousness regarding virtual environment transitions is a relevant indicator of positive user experience during those. Furthermore, serious games taking place in purely virtual environments have the advantage of coping with various workplace configurations and tasks that the trainee can practice. However, the virtual world of serious games should be carefully designed in order to avoid traumatic experiences for trainees. The results presented stem from an empirical evaluation of user experience conducted with 80 volunteers. This evaluation shows that more than one-third of the participants did not even notice the VE global change.