The layout of B&B premises varies. Not uncommonly round here is a detached or semi-detached house with the house being used for B&B guests, the kitchen at the back being extended to catering size, and then owner's accommodation in a further single-storey extension off the kitchen in the back garden. This means that the main access to the guest area is through the kitchen (shared for catering and domestic purposes) and if that is knocked out by fire the only other access is through the garden, round the side and in through the (locked) front door.
Small B&Bs also often have individual locks to each bedroom, rather than a master pass-key system, making it slower to open all the bedroom doors (and probably requiring both hands to do the "yale" lock and the door handle).