A question of panic selling was already discussed on this forum a billion times. But whats bad here? If you are sure that the price will grow back then you can just buy some BTC in better rates. The more dangerous will be the situation when someone is buying BTC while being afraid of loosing some profits despite the fact that pump has already happened (I'm calling it a panic buying). Thats seems like a straight way to lose money and make a bubble.
Panic buying or what we call FOMO (Fear of Missing Out) will cause panic selling because there is a high probability that after the pump, a dump will happen and price would plummet and since those people who bought at the top would see the price decrease rapidly, they would then think of their money losing some value and then think of selling to avoid losing more. During this time when bitcoin is getting more popular, there would be more people joining the cryptoverse and most probably just invest without even knowing what bitcoin is all about and how volatile it is. Seeing it decrease rapidly for thousand of dollars in just one hour would cause a roller coaster ride of emotions that is enough to make them sell. I can see a lot of post in social media asking why the price is like that because they thought it would just keep on increasing. Oh well, welcome to the crypto world!