Firewall for Trunk w/ Nitrous and battery!

When I first put the battery in the trunk of the Duster, I used 24 guage
steel behind the seat. I was able to use the cardboard panel for a template.
Then just made it bigger to mount it in there. I was still able to put the
cardboard back in ther also. Nice for driving. Alot quieter. The tech guy at
the strip had no problem with it.
It worked out great cause it said 24 guage right in the middle where the
tech guy could read it.
Now with the nitrous bottle in there, no one has complained about the
thickness of the firewall.
What really gets me is the fact that with the rear speakers in there, it's
ok. What would happen to the speakers if there was a fire. Boom!
They never say anything about that.