Q: The brake pedal goes all the way to the floorboard

Two times in the same day the brake pedal went all the way to the floorboard. One of those times I was fortunately at a stop sign; the second time, I was at an almost-complete stop. This is so dangerous and I am scared to drive my SUV - what if it happened and resulted in an accident or injury. I have been to the dealership and I was told that the brakes are in proper working order and that they could not replicate the problem. They also told me that my 2013 model is equipped with an entirely different brake assembly than the prior years’ models, which had a verified brake-booster problem. From what I have observed, I am considering that there is a problem with the hydraulics in the master (booster) cylinder. In your professional experience, what do you think is causing the brake pedal to go all the way to the floorboard?