That is a trick you can do anywhere a button is locked and you can go to the previous sector. It's complicated, but basically a hook (interactive object) can be placed inside the level (it's always loaded) or inside a sector (only loaded in the sector). Buttons were placed into a specific sector by the developers, so if you go to the previous sector, the button unloads, causing the button to become unlocked, but the sphere and effects remain. Another instance of this is in Helvetia where you need to fight the 100 formations or something (can't remember

), there you can also go back and skip the lock. Thank god this bug is possible, because otherwise that would have been the end of your no combo adventure
