Complex sentence: The three-story building of the town's which Sato escaped to was submerged by the tsunami, and out of the 130 people who worked at the town hall, Sato was one of only 30 who reached the roof and one of only 10 who survived.
Split into simpler sentences: The three-story building of the town's which Sato escaped to was submerged by the tsunami. Out of the 130 people who worked at the town hall, Sato was one of only 30 who reached the roof and one of only 10 who survived.