Complex sentence: After an emotional conversation, the two men agree to discontinue the fighting but at that moment one of the Soviet troops--perhaps an undercover KGB asset--suddenly hurls a grenade, which kills both men.
Split into simpler sentences: After an emotional conversation, the two men agree to discontinue the fighting. However, at that moment, one of the Soviet troops--perhaps an undercover KGB asset--suddenly hurls a grenade, which kills both men.