Complex sentence: The villagers then turned to stone when they looked at the beam of light from Hendrick's house, as Professor Brake and Matthew escaped to the Sanctuary, just as the ancient travellers had done in the original circle.
Split into simpler sentences: The villagers then turned to stone when they looked at the beam of light from Hendrick's house. The professor and his son then escaped to the Sanctuary, just as the ancient travellers had done in the original circle.