It depends on the situation so better study the current trend.
There are chances that you can get a decent profit out from buying during the sudden rise. Analyzation must take place here because as always, you will lose money here if you don't play it right and the execution goes wrong.
Well yeah those sudden pump can really give huge profit especially when you bought the coin before the hype but buying during the sudden rise is another story as you might get left out and loss more instead of profiting just like what happened in trx when some make an entry during the hype and suddenly the hype subside, and voila it's gone.