Is this the place you're talking about?

If it is here's an excerpt from one of the guides on gamefaqs.com on how to get the box:
One of the walkthroughs on gamefaqs.com
First lure the Gnosis by standing behind box on the left so that Gnosis destroys the box. Then stand behind the electrified fences to lure both Gnosis in touching them. You can now collect 200 G and 2x VEIL without interruption.