Russia walked out, Red China was thrown out, and Czechoslovakia abandoned the Soviet satellites Saturday afternoon during "Massachusetts' first" model United Nations session for 500 "delegates" from 33 Boston high schools gathered in Sanders Theatre.

The all-day sessions, sponsored by the U.N. Council, came to a climax when the "General Assembly" voted 35-6 not to seat Communist China in place of Nationalist China. Red China delegate Charles Cooke demanded his right to be seated, and was finally ejected by the ushers.

Czechoslovakia surprised everyone by denouncing the Soviet purges in that country, voting against seating Red China, and seceding from the Soviet block.

At this point Russian delegate Allan Solomon of Brookline High picked up his papers and walked out, saying, "You'll be purged too when you get home."

The proceedings were further complicated when Nationalist China's representative, George Chin of Chelsea High, began his speech in Chinese and demanded an interpreter. Members of the audience, some of them wearing turbans and berets, shouted at him to speak English. Chin did so.