Yes, maybe the title may be confusing, but this image says it all:

I got a Lepin city set not too long ago, and it included this box. I have no idea how this happened but during use the door mysteriously got stuck inside the box. I'm not really surprised since the set came with an excessively loose head, but I need to get this door out of the box.
Part seperators are too big and bulky to fo the job, so that's not an option. I don't have any minifig crowbars either, and using my fingernails hurts and aren't strong enough. Alternatively I use that golden sword in the picture to grip the handle and attempt to pull out the door but the space available to move the door is very limited, and it gets too tight. Thus when I keep pulling the sword starts to bend, and eventually it loses grip and drops the door. I tried this method countless times and have had no luck.
What can I do? How can I get the door out of the box? (obviously it shouldn't require damaging parts)