Firewall Help

[legacyy21]

Hey guys hows it going? Tonight I was planning on hooking up my amp in my car. I've read up on people going through the firewall behind the computer. My only problem is that I got one of the bolts out, but the second one would just spin and it wouldn't tighten or loosen. Do you guys know how I could get this out, or is there any other easy access places that I could try to get the battery wire through?

[AfterYou]

for the turning, and no tightening or loosening, could be because of a bolt on the other side that you would need to hold with a wrench