954. Messengers of a Mitzvah
135:19 Those who have been sent on a mission to perform some mitzvah, even at night when they are in their hotel, if they are troubled by having to search for a succah, or if it is not comfortable for them to sleep in a succah, or if doing so will affect their ability to properly fulfill their mission the next day, they are exempt from the succah. Otherwise, they are obligated in the mitzvah.
135:20 If guards watching over such things as gardens, orchards and produce are able to watch everything from one place, they should make a succah for themselves and dwell in it.