Read what I said.
That would depend on what you are accustomed to drive and since you never drive a car with a foot clutch why on earth would you even try to press the accelerator at the same time as the brake.
For rather different reasons actually. With a manual car you need your left foot to control the clutch. In an auto your left foot is free to brake and the chances are it is actually quicker to brake that way than moving your right foot from accelerator to brake as needs must in a manual car. All you need to do is lift your right foot off the accelerator at the same time. All that takes is a little bit of coordination, less than that required for an emergency stop in a manual car.