On March 1, 1954, Flores together with fellow Nationalists Lolita Lebrón, Andrés Figueroa Cordero, and Rafael Cancel Miranda entered the United States Capitol building armed with automatic pistols and fired 30 shots.

The Party repudiated the "Free Associated State" (Estado Libre Asociado) status that had been enacted in 1950 and which the Nationalists considered a continuation of colonialism.

Flores continued to hide in the forests and mountains unaware that the FBI was after him, not because of his participation in the revolt, but because he had avoided conscription and refused to register for the draft.

He met fellow nationalists Lolita Lebrón and Andres Figueroa Cordero during one of his visits to the party headquarters.

In 1954, Lebrón received a letter from Albizu Campos, in which he declared his intention to order attacks on "three locations, the most strategic to the enemy".

Lebrón presented the plan to the Nationalist Party in New York and choose Cancel Miranda, Flores and Andrés Figueroa Cordero for the task.

[7] Lebrón intended to call attention to Puerto Rico's independence cause, particularly among the Latin American countries participating in the conference.

The representatives of the House were discussing Mexico's economy when suddenly Lebrón gave the order to the group to quickly recite the Lord's Prayer.

The trial began on June 4, 1954, with judge Alexander Holtzoff presiding over the case, under strict security measures.

[12] On October 26, 1954, judge Lawrence E. Walsh found all of the accused guilty of conspiracy, sentencing them to six additional years in prison.

In 1970, Flores, together with Collazo and Cancel Miranda, participated in a prison strike and stopped working because of the abuses by some of the guards against them.

[15] That same year, President Jimmy Carter, under national and international pressure, commuted the sentence of Cancel Miranda, Lebrón and Flores.

[16] Andrés Figueroa Cordero had been released from prison earlier because of health issues related to his terminal cancer.

There he gave a public speech where he stated: He then traveled to New York City where he was scheduled to appear before a crowd at the Church of the Apostle San Pablo.

[2][3][4][17] In 1979, Flores, Lolita Lebrón, Rafael Cancel Miranda and Oscar Collazo were recognized as the embodiment of the directive of their teacher Albizu Campos to exercise valor and sacrifice before representatives of fifty-one countries at the International Conference in Support of Independence for Puerto Rico, held in Mexico City.

He managed a boarding house and continued his political activities involving the advocacy of Puerto Rico's independence.

He was in a coma for three months and on March 20, 1994, he died in his home which was located in Hato Rey, a suburb of Puerto Rico.