Following the question about arming the door, the link states that doors are usually armed before engine start. What if something goes wrong when passengers are already boading with doors un-armed how to escape from the airplane?
The door the passengers are loading through is obviously one route, back down the jetway or stairs.
The door being "armed" does not affect whether it can be opened or not. When the door is armed, opening it will also automatically inflate the escape slide. When the door is disarmed, the slide will not inflate.
Additionally, each door has a manual inflation handle for the escape slide which the crew can use to deploy the slide if needed.
I could not find a non-copyrighted picture to include.
If the passengers are boarding, the stairway or jetway will still be in place, so this would still be the main route to evacuate the aircraft. There is no requirement for the door to be armed and for the slides to be triggered during an evacuation while the aircraft is still "docked".
If there is an emergency onboard after the stairway or jetway has been removed, but the door not having been armed yet, the evacuation slides can be trigged manually if they are needed.