The next morning, at around 5:15 A.M., Barnes and her assistant Rachel venture in the storm sewer to investigate the scene of the incident. They discover the crack in the ground that released the gases earlier. While taking samples, a more powerful earthquake strikes and Rachel is killed when she falls into the crack that is later engulfed by a rush of the hot gases. A subway train derails underground and power is knocked out across the city. Minutes later, steam explodes from the sewer system. In the La Brea Tar Pits, volcanic smoke and ash billow out, followed by lava bombs that burst out of the tar pits, which ignite several buildings.