The relay click sound you're hearing should only happen when a relay turns on, and when it turns off. There is no sound when a button is pressed - you can check this by loading an empty simulator and pressing any of the buttons at the bottom (the simulator won't make any sound):

https://minivac.greg.technology/simulator/

((Once/if I get to see a Minivac in real life, I may learn that buttons do make sounds..))

When a relay turns on and off, a sound is played. In the following circuit, check this by pressing and releasing the button 1:

https://minivac.greg.technology/simulator/#wires=1%2B%2F1C%2...