Complex sentence: Helo and Caprica-Boomer first had sex in "Six Degrees of Separation"; in "Colonial Day", Helo discovered that Boomer is a Cylon and fled from her.
Split into simpler sentences: Helo and Caprica-Boomer first had sex in "Six Degrees of Separation". In "Colonial Day", Helo discovered that Boomer is a Cylon and fled from her.