I was going through the SAFE User Guide by YC (https://www.ycombinator.com/docs/Post%20Money%20Safe%20User%20Guide.pdf) and in the section - Basic Mechanism Q5 (page 8 ) "What happens to a safe if the company shuts down and goes out of business?" it says that "The safe holder is entitled to receive its Purchase Amount back". My question is who pays the investors back? The company that shut down? And where do they get the funds to pay back?