Complex sentence: While awaiting interrogation, the trio is freed by Detective O'Brien, who discovers that Kyle and Sarah are time-travelers, and thanks them for saving his life from the T-1000's attack back in 1984.
Split into simpler sentences: While awaiting interrogation, the trio is freed by Detective O'Brien, who discovers that Kyle and Sarah are time-travelers. He thanks them for saving his life from the T-1000's attack back in 1984.