A tsunami survivor is on the beach. They see the ocean recede into the distance and realize what it means.
So they start alerting people to what’s coming. But rather than listen, the people ask their friends what the water receding could mean. And their friends give them all kinds of answers. And many of them are reassuring.
“It’s a hoax.” “We haven’t had a tsunami for 100 years.” “I’m sure it will be fine.”
So they do very little when they could be doing a lot.