If a disaster strikes there are multiple layers of responders. First-level responders which include fire department, paramedics, police, etc. But, before first responders arrive you may need to rely on pre-first responders called CERTs, or, Citizen Emergency Response Team. CERT training is pretty extensive and extremely informative. When a disaster strikes, the CERTs organize, provide very basic first aid, assess damage, triage victims to aid first responders, and help create some order from the chaos. I highly recommend that everyone go through CERT training.
The first priority taught in CERT training is to protect yourself so that we can help others. If you become a victim then (1) you need assistance and (2) you will use limited resources that could have been used for others, and (3) you can no longer assist others. Think of the instructions when on an airliner. If the plane loses cabin pressure you must don your mask first and THEN assist others. If try to help someone else first and lose consciousness you cannot assist anyone. This is bad for you and bad for those who you could have helped. During these incidents you must ensure your safety so that you can be help rather than hinder.
In times of crisis your first priority must be to protect yourself. Protecting yourself protects others. For example, consider an epidemic such as the coronavirus. If you contract the virus then you become a carrier and you could infect dozens, hundreds, or thousands of people. If you become sick you will also use some of the already limited resources (medicine, doctor’s time, hospital space, etc.). The resources that you use reduces the resources available for others.
If treatment and rescue services become saturated then your care may require someone else to suffer or die. In Italy during the COVID-19 pandemic there were not enough hospital beds and ventilators. The medical staff had to triage victims and choose who would get the limited number of ventilators. Those with the best chance of recovery were treated and those with less chance were left to die. During the worst part of the crisis for each person saved there was another person who died. This is an extreme case but a very likely scenario in the event of a major disaster.
While protecting yourself may sound selfish it is one of the best ways to make the situation better. You do not become a victim and you are better equipped to help others.