Well, you are generally safer to stay indoors, but not 100 percent safe. Most people who are struck by lightning are injured when they are outside (and many injuries and deaths occur when people stand next to trees, so trees are not the best place to find shelter). There have been incidents, however, when people inside their homes have been injured as lightning runs through power lines and pipes and can escape through appliances and plumbing indoors. In one incident that occurred in Chicago Heights, Illinois, on October 24, 1991, a lightning stroke made its way through a cable line, entering a house and causing a bed to catch fire. Such cases are quite rare, however.