SOR 1013 Two Approaches

The Boeing Starliner was used to transport a crew of two to the International Space Station (ISS). But there were problems. And it was deemed too unsafe to return them to Earth. So the Starliner returned to Earth without its crew 'safely.' So was it safe? What does it mean to be 'safe?' What does NASA think 'safe' is? What do you think 'safe' is?