Complex sentence: The only thing Buffy did manage to do was escape during a temper tantrum by Glory which caused the building to collapse, escaping with the last surviving monk who quickly revealed to her the truth about Dawn being The Key and Buffy as her protector.
Split into simpler sentences: The only thing Buffy did manage to do was escape during a temper tantrum by Glory which caused the building to collapse. Escaping with the last surviving monk who quickly revealed to her the truth about Dawn being The Key and Buffy as her protector.