In planning and implementing the 5 Principles for Mass Casualty Intervention it would be impossible to begin after a mass casualty event from an unprepared base. Promoting sense of safety, calming, self- and community-efficacy, connectedness and hope, the 5 principles demand attention to both complex psychological processes and messaging. They also have profound implications that affect realities on the ground that require coordination with government, emergency services, hospitals and clinics, major media, website formulation, and communications technology. Such complex programming must be developed with forethought and require time to build these bridges, achieve funding, and create “templates and policy” that are ready to be served up. Moreover, dissemination and information sharing (marketing) must occur prior to attacks or disasters, so that the public and those who must team together have foreknowledge on how to navigate during the golden hours. Since the 9–11 attack on the World Trade Center and other terrorist attacks in France, Great Britain, school shootings, and several monumental major disasters there has been increasing recognition of a need to create and form policy. Rather than being published in a formal sense, most of this work has occurred on an organizational level, especially by NGOs but often with government involvement. The WHO has also been instrumental in aiding policy formulation as well as participation in field implementation as has the International Red Cross and Red Crescent Societies. Hence, work in the “golden hours” need to be part of prepared plans that are ready for implementation, with the attendant cross-communication between government, first responders, mental health organizations, hospitals, and community organizations. A second important factor to consider in implementation is that under-resourced communities and individuals are both most vulnerable to attack or the devastating impact of disaster and the least able to engage with aid. This means that bridges need to be made ready for enabling them to profit from intervention. Interventions are only successful when individuals and communities have the means to engage them, and such means must not be assumed. Evacuation will not occur if people believe they will lose the rights to their homes or they must abandon their elderly. Even those who have not experienced prior disaster or mass casualty may have an impaired sense of safety and compromised trust in police and government. A third critical factor is the fundamental understanding that the “golden hour” is not the first “golden hour” for many individuals or communities. Terrorist attacks, refugee flight, war, and natural disasters are often repetitive, such that trust, safety, hope, social connections, sense of self and communal efficacy, and psychological calm have already been impaired or devastated. The poorest and least well-resourced in any community are those most likely to already been harmed through everyday events of violence and tragedy or prior mass casualty. Knowing that the “golden hour” of intervention occurs on an already weakened and damaged base is critical.