Complex sentence: Kristian enters the hotel, but after locating his son's backpack, he reaches the conclusion the rest of his family is dead and goes into a grief-filled rage, angrily banging some exposed pipes with a metal rod.
Split into simpler sentences: Kristian enters the hotel, but after finding his son's backpack, he falls into depression, surmised they have perished. Enraged, he undergoes action of rage, angrily banging some exposed tubes with a metal rod.