“total failure of its braking system.””
BS.
There’s always the park brake and the ability to turn the steering wheel to go uphill to then put the trans back in PArk.
Besides the parking brake, one can turn the ignition off and let the engine decelerate the car, once it slows enough jam it into Park or Reverse. I think if I were headed towards a busy highway with cross traffic, I would spin the steering wheel and hit anything else rather than ram into cross traffic.
If you don’t believe that “shiite” happens, then stick around a little longer.
Some day she will laugh at this story, but not right now.