Stepped on brake when cruise control engaged and car accelerated.

What is your question?

When car was set on cruise control at 70 mph, I lightly stepped on the brake and the car suddenly accelerated as if I floored the gas pedal and went into passing gear. The difference was that it accelerated 5 times as fast when I stepped on the gas pedal. There is a slight delay when the gas pedal is floored causing the car to go into passing gear. I will be taking the car to the dealer to check it out. Any feedback is appreciated.