It's a pretty straight forward and simple exploit, so it feels like it should've been found by now. But I did
some searching and didn't really find anything, so I apologize if this has been posted before though.
With this you can walk through instance doors that require previous bosses to be killed in order to open.
I have only tried it twice in BG, and haven't gotten it to work yet.
How to:
1) Walk up against the door.
2) ALT+F4
3) Once the loading bar hits 100%, tap the autorun key once and wait (Don't be too fast or too slow).
4) Watch as you pass through the door.
Both me and my brother, as well as a friend managed to do this without any trouble. The faster your computer is, the harder it'll be to time it, though.
While you're disconnected your character remains in place. Once your loading is at 100% you can technically start moving it seems, which means your character moves forward in between the moment the world has loaded and the moment when doors and objects load.
Some visual aids down below: