Moved by the stories of Ukrainians tortured by the Soviet secret police in Lviv, Antoniv chose to undergo an underground independent education, and additionally attended secret services of the Ukrainian Greek Catholic Church after it was banned and forcibly merged into the Russian Orthodox Church.
During this time, she first met Zenovii Krasivskyi as part of her efforts to support political prisoners from the Ukrainian National Front [uk].
With the beginning of Mikhail Gorbachev's policy of Perestroika, Antoniv sought to campaign for the legalisation of the Greek Catholic Church.
Prior to her death, she, along with Krasivskyi, had been on the way to a birthday party for Raisa Moroz when Antoniv got out of the vehicle to buy flowers.
[2] Shortly after Antoniv's death, exiled dissidents Sviatoslav Karavanskyi and Nina Strokata Karavanska published an article in the Anti-Bolshevik Bloc of Nations Correspondence accusing the Soviet government of masterminding it, further noting that it took place two days prior to another car crash which killed Juozas Zdebskis [lt], a Lithuanian Catholic priest and Soviet dissident.