OK, don't panic!
Either:
1. Buy and jack and cut the nut off once you have the proper angle $20.
2. Buy a nut splittler, this will basically "crack" the nut in half, and you can pull the bolt out. $20.
Either way, you win. Every man needs a jack. Every man also needs a nut splitter. In my case though, I'm married.
Seriously, don't cut into your pipes. I think it would be a bad idea...