The Badass Moment:
Svoboda pulled out a pistol, held it to his own head, and said, "If I kill myself, my blood will be on your hands, and no one in the world will believe you did not murder me."
Everyone in the room knew he was right: Czechoslovakia had recently established some progressive reforms to see if they could reboot communism into something less oppressive and murder-y. In response, Brezhnev launched some significantly more oppressive murder blitzes, invading with 500,000 troops, capturing the 26 politicians, and forcing them to sign the Moscow Protocol -- a commitment that would undo all of their work. The world didn't know all the fine details yet, but they understood that things were fairly tense between the two countries, so if a highly respected veteran of both world wars had shown up with a cannon blast in his forehead, it wouldn't have been great for the USSR's image.
Czech roulette uses every chamber.
The prisoners were released only hours later, and then immediately given vodka "so they could become human beings again." (That's not a joke, just an accurate description of how things happen in Russia.)