Some Lockheed employees rushed to retire Friday, to avert losses to their savings plans stemming from the sharp decline in the stock market last month. Employees who retired in October had their stock holdings in Lockheed's savings plan, known as a 401(k), valued on the basis of the Sept. 30 price of the shares in their portfolios. Bryan Carver, president of District 727 of the International Assn. of Machinists, which represents Lockheed employees, said the stock decline "has a lot of people in panic around here." A Lockheed spokesman said 500 people retired in October, up from an average of 300 per month so far this year.