Background: The number of intentional mass casualty incidents (IMCI) has increased in recent years, and hemorrhage control is one of the important life-saving techniques used in these events. Objective: The objective of this study is to understand the perceptions and experiences of nursing students sub-jected to a simulated intentional mass-casualty incident after receiving a training action within their curriculum, focused on how to respond to active threats and bleeding control. Design: A qualitative phenomenological study on nursing students (n = 74) enrolled in the Nursing Care for Critical Patients course, facing a simulated IMCI in November 2019. Data sources: A total of 7 focus groups were performed, containing 8 to 12 participants each. Findings: Participants reported a feeling of vulnerability and fear of an IMCI occurrence. Based on this context, the participants reported not knowing how to react to this type of situation, which is why training activities such as this one is seen as a way of improving participants' self-protection and safety. Likewise, a simulated IMCI is considered useful for any citizen and as a training exercise for life-saving techniques, such as hemorrhage control. Conclusions: Training on the subject of hemorrhage control using a simulated IMCI setting could increase self-efficacy and self-control, as well as reducing feelings of fear and vulnerability. Such training intervention could be primary prevention measures of an IMCI as well as a sustainable way to train knowledge-transmitting instructors.