without any cap it doesn't look fun for the unlucky person. Take a look at my other comments on this thread, there's a link to a gist that generates an animation with the same starting conditions as OP, but forcing the person with $0 to borrow and introducing an interest rate of 10%. At some point the system destabilizes and the debt of the unlucky person goes out of control.

TIL what an economic crisis is and how it happens