Car engine stopped

Vehicle listed above has never had any mechanical problem to date and had not been leaking any fluids). It quit while I was backing up, then it started okay. There were no warning lights on. A few minutes of driving later, I heard a ticking, slightly whirring sound from under the car, and it started to lose engine power, labored for a mile and a half, and shut off. It didn't start-up then. There was a quart or more of oil/antifreeze that ran out from the center passenger's side, and under the hood, the antifreeze overflow was at max level, but bubbling fiercely. There was a very hot smell from the engine. The oil dipstick said no oil was present. The shop has only said that they found an antifreeze leak in the motor, and they would be doing further diagnosis. Have any idea what might have happened?