Complex sentence: Carrie tries to call Quinn but only finds that his number is out of service, after which she visits Adal, demanding to be put in contact with Quinn, but Adal says that Quinn has gone on the mission in Syria and cannot be reached.
Split into simpler sentences: Carrie tries to call Quinn but only finds that his number is out of service. Carrie then visits Adal, demanding to be put in contact with Quinn, but Adal says that Quinn has gone on the mission in Syria and cannot be reached.