I don't think there is a shortcut key for the guard buzzer? (I don't see it in the list of commands, and a quick press of all my keys didn't work out ) It is a small thing, but such a keyboard shortcut would help to shave off valuable seconds on a service.
Also have the guard give the right away (two clear buzzes); stop (one buzz) and close door (two buzzes then one buzz) signals.
