are you sure you mean TECHNICALLY and not actually PRACTICALLY?
Yes, the amount of time you have to stop pressing based on feeling the bump/sound is too short for you to react to it...so the time it takes for gravity to bring a cap down 2 mm is like .02 seconds....
Just to put this in perspective...in the Olympics it is considered a false start if you're moving within .09 seconds of the gun..but let's just give someone the benefit of being twice as fast as that so .045 seconds.....and say you're pressing half the speed of gravity..that is still .04 (time from 2mm to 4mm in depth) vs. .045seconds which is twice as fast as they allow for an olympic athlete.
Granted, the numbers are taken off of things like track and field reaction time, etc...but really it is to put it in perspective...You're not reacting to the click or the bump..It might've helped you get used to how hard you need to press...but you're not reacting to it...
not reacting, more like anticipating.
When i was younger and had just begun learning guitar, i used to tap my fingertips on hard surfaces (high repetition, low pressure... not "slam"), when i was between activities but away from my guitar. Having metal wires cutting into your fingertips hurts. Typing doesn't hurt.

(unless we start talking about tendons, ligaments, nerves and other connective tissues...)
Also: ALWAYS(!) use the opposite hand for shift. The only place i ever same-hand-shift is 'Z' or '?' (but not this time) (okay actually, i break that rule in gaming sometimes/often, because my right hand is busy w/ the mouse... but that's an entirely different beast) If your right hand needs to do the key press, your left hand needs to do the shift. I won't be a super hardass and demand you always use your pinky, though. Some pinkies are practically vestigial. But really, the pinky is the only one in position without requiring much lateral hand motion (if any). I'm also a right-thumb spacer, so make of it what you will.
Just like with guitar, i'll advise anyone to use their pinky as much as possible, and try not to "anchor." If that doesn't work out for you, i understand. If whatever you're doing starts hurting, take a break.