Emergencies have been my specialty in life. I can be calm in the midst of chaos. I have had to respond to urgent life/death situations and know how to table my emotions and act quickly. The emergencies have been helping others with mental illnesses to get to a hospital.
If this hasn't been part of your experience in life, perhaps you could imagine dealing with a visual - an avalanche, an earthquake, a tsunami. You have seen films showing such events.
The only way to help unstable people is to stay very calm, think quickly on your feet and ACT. If you get caught in an emotion it will be similar to a squirrel perched in front of an oncoming car playing dead - nice effort - wrong response! If another person is freaking out, you CANNOT and SHOULD NOT try to reason with him/her. A hospital is a safer haven than the outside random world to bring an unstable person who could hurt himself/herself or another. You can soothe that person on the way to a hospital by listening, let them speak instead of persuading them to see things differently. This does not mean to be directed by the unstable person. You can stay calm and may or may not help the other person by saying things like, "I understand. It will be okay. No problem." Try to use words of encouragement.
What dealing with emergencies has helped me recognize is that during periods where we have more time and quiet, peaceful times, one CAN choose to relax, instead of creating conflict and unrest. After a lonely feeling solitude arrives. My last post talked about how one's home may be a sanctuary. It doesn't seem to happen without effort for me, however. The ability to "just be" is not a typical New Yorker thing. A friend who is Chinese told me at this time of year, since the temperature is changing, it is becoming YING. She told me that the Chinese have a tradition to sit outside and look at the moon and eat mooncakes. I want to try this.