Those sold at 170 could easily sell at 210 now, and that's more than 20% difference.
Of course,
if they had known at $170 that price would soon stabilize at $210, they could have easily waited. But they did not know it, that is the whole point.
What I mean was when there's a panic sell, you can expect a rebound almost for sure. Most people know it but just be too afraid to lose everything or too greedy, thinking they can buy back at lower price soon.