Apparently one of the Boss 302 testers had a brake clevis pin snap, and the pedal itself was incorrectly installed, resulting in zero brakes. Luckily all Boss 302's have actual manuals (hooray for Ford!) and the driver was able to go down through the gears and save the car.
The only thought is that maybe the master cylinder had been pulled and replaced, and whatever monkey that hooked the brake pedal back up did it wrong. Except nobody has any proof that the MC ever came out of the car, so it could have equally been a production-line error.
Bravo to Ford for shutting down the Mustang line and trying to figure out the issue though.
