When they ran out into the street, someone asked if there was anyone else in the house, thinking that Ted Gold, the other Weatherman in the townhouse, had gone to the store, Wilkerson replied that no, there was no one left inside.
No, there was no one left inside. Someone asked if there was anyone else in the house, Wilkerson replied this. Ted Gold had gone to the store. This was what anyone else in the house was thinking. They ran out into the street. Ted Gold was the other Weatherman in the townhouse.