The security door of my newly bought house opens inside and outside next door. If I drive outside, the size doesn't affect the next door. I want to change it into an outer door.

Your users here should all be the same as you. Look what others have done. I can only give you two suggestions: 1. Remove the existing door and install it in the house, and change the lock with the security door company (or maybe not). This will not affect the fire fighting, but also have space (such a door will occupy at least 3/ 1 of the door width). 2. Put a shoe cabinet outside the door, to the left of the restaurant inside the door. Put a glass photo frame on the right side of the door.