In my experience, The panic selling is for not experience here in bitcoin or didn't know the market speculation. For me if the price drop down I will wait because I know that bitcoin price will pump again and for every year that is happening dump once pump twice. If you trust bitcoin you will not do the panic selling.
You could actually take the advantage of this panic selling which in other words is know as trading. I didn't really care of panic selling much as I even knew that the price will increase soon , I had taken advantage of panic selling only once and made a profit of 200$. But mostly panic selling occurs in china.