She manufactured bombs for the SR Combat Organisation, which used them to carry out assassinations against the interior minister Vyacheslav von Plehve and Grand Duke Sergei Alexandrovich.

[1] After participating in a political demonstration, Brilliant was internally exiled to Poltava, where she met the revolutionary socialist Grigory Gershuni.

Brilliant demanded to be the one to throw the bomb, but Savinkov overruled her, as he believed women should not commit terrorist acts if men were there to do so.

On 2 February 1905, while Brilliant kept watch, the intended assassin Ivan Kalyayev failed to carry out the attack, as the duke's family had come with him.

[12] Kalyayev refused to give up his comrades, including Brilliant, to the police, allowing her to continue making bombs for the SR combat organisation.

[17] In the 1909 novel The Pale Horse, Boris Savinkov gave a fictionalised account of the assassination of Alexandrovich, portraying Brilliant through the character of Erna.

[18] In the 2004 film adaptation of Savinkov's novel, The Rider Named Death, Erna was played by Kseniya Rappoport, who bore a resemblance to Brilliant.