As was said, a competent shooter who doesn't have any serious physical obstacles to performing those actions should be able to do it in less than two seconds.
This is not including any time that is necessarily used up in all the other things that are inherent in a gunfight, like making decisions, pulling aside clothing, moving away, standing up, leaving the car, etc. At a firing line? 2 seconds. At any other time in your life, it would be more accurate to say 5-10. When the loudmouthed guy at the little league game goes postal and starts shooting at the umpire, you're going to have to put down your hot dog and coke, jump to your feet, and unzip your fanny pack before you can draw and double tap, right?