Well, that's fairly good advice. You might not want to approach this chore like a bull in a china shop. Tap it out would be a bit better idea than hammering it out. That firewall is only a piece of 1/4" ply (probably) and you can rip it out of the plane if you are to agressive with your repair. They are not china, but they are not iron either. You can break things if you go at to agressively. Be careful, and focus on taking out the blind nut and doing the least amount of damage (like no damage) in the process. It should come out fairly easily, but don't over do it either.

CGr.