Emergency door controls on almost all service buses I’ve come across are simple air valves, independant of electrical systems, so isolating the electrics won’t make any difference to their operation. Even if the bus had a pretty serious air leak and the air depleted, then the doors would simply be able to be easily pulled open - if they hadn’t already started to. The only exceptions to this I’ve come across are the mellor breadvans and merc sprinter type conversions.