In the basement of George Washington University's Lisner Auditorium, it looked at first glance like your everyday St. Patrick's Day party--beer kegs in the corner, Kelly green balloons, Kelly green dresses, shirts, pants, ribbons, carnations . . . Even the handpainted sign that proclaimed "Match Day '82" had a green (of course) shamrock painted beneath.

Match Day, the day fourth-year medical students find out where and what their post-graduate training will be, is something like a cross between Sadie Hawkins Day and Armageddon. Waiting for the ax to fall, for the Roman candles to zingggg.

"Omigod," sighed a green-bedecked young woman, "I'm so nervous I can't stand it."

Joe Mastromarino was wearing a bright red plastic fireman's hat with a battery-operated flasher and a small-voiced siren. Even before he opened his envelope he was "certain" he would be going to the Hershey Medical Center in Hershey, Pa. ("Oh Joe," his wife, Vicki, warned, "don't say it before you see it.")

He has, he bragged cheerfully, a collection of 150 hats of varying ostentation. He wore them to exams to shake up the establishment. He was not nervous yesterday. His wife was, a little, as the students lined up to get their envelopes.

"Real theater, real theater," said a student who had "gone outside of the match"--made his own deal, as is occasionally permissible.

Then an explosion of shouts, laughter, shrieks and hugs--and some tears, but mostly of joy.

Moody Mustafa, who grew up in Bethesda, wanted to stay in the area. He carried a green balloon on a long string. He will be at the Washington Hospital Center. "Oh god, I'm really happy," he crowed.

David Federle and his family (wife Carmen and 15-month-old Gus) wanted to stay in the area, too. They'll be at the University of Louisville. (Oh well, they'll be near friends.)

Among the most greenly dressed students were Anne Moss and Brendan Buckley (who sported a green button reading, "Let's hear it for the wee folk"). Buckley and Moss entered as a matched pair and shrieked, "We're happy, we're happy, we're happy" to discover they would be at the University of Massachusetts (with four of their classmates). "I'm happy, I'm happy," cooed Marie Amos. Amos, who was Montgomery Blair High School student government president in 1975, will study internal medicine at Mercy Hopsital in Baltimore. She is 24 years old.

The way it works:

Fourth-year medical students apply to a number of programs in their fields in the geographic areas of their choosing. After applications and interviews are reviewed, students list up to a dozen or so hospital programs in order of preference. At the same time, the hospitals list the applicants in the hospital's order of preference, sometimes listing upward of 100 students.

All the lists go into a computer in Evanston, Ill., where careers and lives are determined by the flick of a microvolt.

The scene at Lisner, where 114 of GW's 150-plus about-to-be doctors were waiting for their envelopes, was repeated all over the country yesterday as more than 10,000 medical school seniors in 126 schools got the crucial word.

It could have been worse. Those students who, as it is put, "didn't make a match"--didn't get any of their choices--had been notified by the dean on Monday. By yesterday at 11:55 precisely, when their classmates were opening their envelopes, the six at GW had already found other places not on their lists. "Nobody," whispered Vicki Mastromarino, "is out of a job."

Statistics: At GW, 81 percent of the class got one of their first three choices. More than half got their first choice. Over at Georgetown the story was similar. Only three nonmatches.

Money: Most of the students graduate in debt. The average debt is about $20,000. One two-doctor couple who will go to Baylor University--Laurie Brown and husband Kevin Goehl--owe "a lot of money and he owes three years to the Public Health Service. Time and money."

Joe Mastromarino's confidence was justified. He said he was firing off a telegram to the program director at Hershey, a long poem he wrote last night, he said, including these lines: "T'was the night before Match Day/And all thru the house/Not a creature was stirring/Not even Joe's spouse," and ending up, " . . . Two cars and a wife and a kid on the way/We're happy to be coming to Hershey P.A."

Once the beer kegs at Lisner were emptied, the 1982 senior class of the George Washington University Medical School was headed to the Twenty-First Amendment for the traditional daylong partying.

Not Mastromarino.

For the first time all day he looked, well, a bit sad. "I'm on call," he said.