Purpose There is a gap in time between the occurrence of a mass casualty incident (MCI) and the arrival of the first responders to the scene, which offers an opportunity for the public (immediate responders) to perform life-saving measures. The purpose of this study was to identify these measures and the public's willingness to conduct them. Method An extensive literature review was performed to identify the possible measures that can be undertaken by the public. A group of experts were asked to prioritize and rank the feasibility of performing the measures by the public. Finally, the public was asked whether they were willing to do the chosen measures before and after an appropriate education. Results Twenty different measures were identified and presented in a questionnaire as statements, which were prioritized and ranked by the expert group into four categories: what (1) should be done, (2) is good to know how, (3) is not necessary to know, and (4) should not be done. All statements were converted into understandable statements and were sent to the public. There were some differences and some agreements between the experts and the public regarding what an immediate responder should do. However, the willingness of the public to perform most of the measures was high and increased after being offered an appropriate education. Conclusion The use of immediate responders is a life-saving approach in MCIs and in situations when every minute counts and every human resource is an invaluable asset. Multiple steps, such as education, empowerment, and access, should be taken into consideration to enable bystanders to effectively help struggling survivors.