Elon Musk defended the safety of electric cars in his first public remarks since a Tesla Model S sedan caught fire in Seattle on Tue. The well publicized incident sparked a brief selloff of Tesla (TSLA) shares. In a blog posting, Musk asserted that gas-powered cars are much more prone to fires and electric cars are safer overall. He said a piece of metal on the road tore through an armor plate protecting the car's batteries. Tesla rose 4% Fri., but were down 5% for the week.