Complex sentence: Buffy looks down in horror at the unconscious Giles surrounded by flames and, as Angel boosts her over the rail makes his own escape, jumps down to drag her Watcher out of the building.
Split into simpler sentences: Buffy looks down in horror at the unconscious Giles, now completely surrounded by flames. As Angel boosts her over the rail and makes his own escape, Buffy jumps down to drag her Watcher out of the building.