Complex sentence: After unsuccessfully testing an antidote on the cook, they leave Ángela, Guzman, Lucas and the old woman in the cafeteria and it turns out Lucas took a sample of blood from the building and know's that the people in charge are the Vatican.
Split into simpler sentences: After unsuccessfully testing an antidote on the cook, they leave Ángela, Guzman, Lucas and the old woman in the cafeteria. It turns out Lucas took a sample of blood from the building and knows that the people in charge are the Vatican.