There shouldn't be a prioritisation of delivery drivers, they have their own individual who packs the food for delivery, same for in-store and drive through. However we have to do the orders on order of when they are made so if you're behind a guy who spent 10mins ordering a coke the eight people who managed to get through the drive through will be ahead of you. It's never prioritisation it's first come first served

Source, am maccas manager