This study concerns the professionalization process of future nursing care professionals. More specifically, it looks at the way of thinking (cognition, evaluation) associated with the violation of hygiene rules. One hundred and fifty student nurses completed an elicitation questionnaire before and after their first workplace training. The elements associated with the violation of hygiene rules demonstrated the acquisition of a professional jargon, heightened awareness of legal implications, and indicated that the activity had a greater causal effect on practice than the agent. Regarding the way the thinking process is organised, we observed a search to bring the elements in line with each other linked to the desirability of the “breach of a hygiene rule” event. Finally, the workplace training seems to have led to a shift from passive control centred on the consequences of violating the rules to more active control centred on consideration of previous incidents and management of the situation.