you can't pull the bar out without removing the lock. You can't remove the lock unless you can get the key out.
Here is a picture of another monkey puzzle. The key is inside.
I am making one now. Hope it comes out working fine.
I know this is a very old thread, but I wanted to know if people are still using this type of puzzle. I don't see them for sale on ebay like is posted above. Are there newer types of puzzles out there now.