My understanding is Miller brought Miles’ gun to Miles. It wasn’t Miller’s gun and Miller wasn’t involved after that.
I don’t know what code of conduct would prohibit this.
Think of this from a legal/jury perspective. What would a reasonable person do? If you get a text saying people are acting tough or whatever and ask you to bring a gun would a reasonable person bring it? Would a reasonable person park their car along with another friend to "block" in the victim? Also text the guy back saying the gun is there and its loaded?
The only reasonable thing he did from the articles I have read is after doing all that he got himself and his GF away from the shooting... which is good since his car got shot. I'm stupid, but it certainly seems like he knew what was about to happen and helped make it happen by bringing the gun and parking where he did. IDK how he didn't get charged with something unless they are waiting for the shooter to get convicted first.