Generally speaking I agree, of course.
But sincerely I still think the loop cannot be melted in 30 seconds.
Anyway, as far as fire protection is concerned, you know we have two loops, A and B.
If one fails, it is automatically deselected, and the remaining one will perfectly work alone.
However , if you do the fire test it won't work! You'll have to troubleshoot by alternatelively select Loop A and then Loop B, to exclude the failed one.
I've never seen people doing a fire test after it has extinguished, and personally I won't change my SOP: that's basically because we have two loops, troubleshooting for the failed loop would increase the workload too much, and lastly because Boeing doesn't say so.
Don't get me wrong, I'm the first one not to blindly thrust the rules or the manufacturer's manuals.
More than once I've criticised some procedures established by test pilots who have some strange ideas.
Boeing too changed some of it's procedures and it's manuals through the years.
There's no absolute truth.
But in this particular case, I guess somebody in 7p3i7lot's Company's brass one morning had a brilliant idea, but forgot to consider all the consequences...