The reason behind panic selling is that people lack patience and they get panic when they see price going down and start selling their coins at cheaper price and I think that is the time when we should hold our coins tight and wait for the price to bounce back again but generally people doesn't follow this simple rule.
It is not the patience that triggers panic selling. It is the lack of knowledge on what it is their holding. Lack knowledge meand lack of faith, and lack of faith means easily get shaken when dumps occurs, may it valid or fake dump. So the first move this people who lack faith is to sell their holdings the soonest the can.
Impatient will also have the effect of panic because if you are patient you will survive and not panic when the price goes down. Knowledge also gives effect. If you have any knowledge of course you know the bitcoin price cycle and want to be patient in holding bitcoin
i don't think impatient are the key factor that can make people go panic selling , the definition of panic selling itself are a condition where the market shows a bearish and a lot of people decide to start selling every single bitcoin they have step by step or even at once.
nobody know bitcoin could go up or down , all we do are just make a prediction and speculation based on the live data.