When idling with my foot on the brake for a period of about 10-15 minutes (without putting the car in park), when it is time to move up, the car takes off and the brake doesn't work. There is a sound. This has happened twice and the dealership hasn't found anything.

put on brakes and car lost control in perfect weather

I was driving and had to put on brakes fairly quickly and the car lost control almost causing an accident. I am afraid of this car now. I have had situation where I had to put on brakes in other cars but never have this happen. this is a 2015 kia optima with less than 300 miles