Complex sentence: The surviving hostages tell how he repeatedly risked his own life in order to save those of the children and how he moved explosives which had been placed near the children, and tried to prevent others from being detonated.
Split into simpler sentences: The surviving hostages tell how he repeatedly risked his own life in order to save those of the children. How he moved explosives which had been placed near the children, and tried to prevent others from being detonated.