[dreamless]

Spoiler:

well, indeed they are still bound by a sense of tradition, to an extent at least, as the sense of tradition doesn't stop them from hiring Mirielle to kill Altena. Actually I guess rather than a "sense of tradition", it's more like the "formality of tradition". They may wanted to bomb that holy place where Altena dwells, but whoever ordered it would look really bad since that's the, well, "holy place" for Soldats...

Also since in the end the girls deny being Noir, there's nothing, whether sense of tradition or formality of tradition, that can stop them from tricking the girls and killing them...

I guess how you wish to interpret the gunshots at the ending depends on whether you are willing to take the romantic "leap of faith"... I guess I'm just not that romantic and I always think an ending with both girls killed fits the theme "Noir" better