I agree with John. Get your local electrical inspector in there, show him the problem and see what you can work out.
From the sound of it, you might be chipping up some floor. These days with diamond saws and air tools, it is usually not that big a deal. You might be meeting a guy from the concrete worker's union tho (in Chicago).
Once you get it opened up you should be able to get back to clean pipe and extend it a little, into your new enclosure or just use a bigger box.