Concurrent to the Hungarian uprising of 1956, there was some unrest in Romania as well, and the Soviet military presence there was strengthened in response. Romania began to oppose the Soviet hegemony in the 1960s—Ceaușescu spoke out against 1968 Soviet invasion of Czechoslovakia, and Romania built friendly relations with the anti-Soviet bloc. So it's not entirely a given that the Soviet Union would not have considered military intervention in Romania at some point like they did in Hungary or Czechoslovakia. You can't excuse the Romanians for wondering how their government could afford to get away with their open defiance of Soviet hegemony.