If there is a code, it's for having a bit if a dust up, a push and shove, face to face, where a couple of punches to the guts might get snuck in unseen, then the deputy headmaster comes in and says "Oi, what's going on" and both of you scuff the ground and say "nothing sir, just a bit of misunderstanding".
THat code goes out the window if you gelt belted from behind, or during the scuffle someone produces a weapon, or sinks some teeth in. THis is what breaks the code, not the ratting out.
Suban standing by his story is calling out Masten for breaking the code by going the chew, not the other way around.
