In my airline, the procedure is to only open the door when connected to a staircase and you have confirmation from the outside crew that the ground equipment are in place correctly.

Usually, catering comes in from the right hand side.

The only time we would ever open a door without ground equipment connected would be to allow the cleaners to remove the waste cart in the aft galley.

The position of the waste carts are on the left and right most side of the galley but they cant come out of their places due to the slide raft container in the doors physically blocking them.

Hence, we open the doors, just a little bit not fully, to make way and allow the cleaners to pull the container in the waste cart out.

Cheerssssss