Considering EVERY day this year has been a huge drop (except one flat day) and foreign markets are down another 3-5% overnight, swift action could save TRILLIONS of dollars in stock value. The markets have already lost about 10% this year, more than wiping out last years gains. Another week, will be another 5-10% decline, minimum. The Fed needs to act NOW.
Day to day fluctuations in stock price are of little effect in the longer term though they can make your hair fall out if you watch your stock ticker every minute.