>nor is your hand calculator a computer, is it?<
Yes it is. Just a very weak one.
I tried on the windows calculator and it took about 1 second to give me an answer.
The quantile of 0.05 for binomilal(0.2,10000) is 1934.
Thats roughtly 1934 seconds of waiting which is a fair amount of time (about 30 minutes).
With 100 000!, I gave up after 30 seconds of waiting.
The time factor increases very quickly.