In the period following the Aster Revolution, as Transylvania's administration was taken over by Romania as a result of the Hungarian–Romanian War, he joined Károly Kratochwill's non-communist Székely Division (formed inside Hungary by Hungarian Transylvanian refugees), which tried to oppose the Romanian military. After the Romanian Army crushed the Hungarian Soviet Republic, Luca moved to Brașov and began working for the Romanian Railways (CFR), attempting to align railworkers' trade union with the Profintern. Luca later admitted that, in Leninist terms, he had been mistaken to leave the Division — after allegedly being persuaded to do so by a group of workers in Satu Mare — as he had missed an opportunity to carry out "revolutionary work under party directives", although he confessed that he had been denied membership in the Hungarian Communist Party.