In the movie, when K is (I think completing the sign up procces for J), There
is a shot that shows a 3/4 view of his back while he is typing and J is in
If you look at his hands (K's) you will see that his hands are not touching
the keyboard but you will hear a typing noise anyway. This is so that the
text that the film makers wanted would appear on the screen.
This technique has also been used in other movies where a actor has to type
fast and get the desired text onto the computer screen.