^ In what way?
Look, we all know what murder is. If Riker had killed Yuta for no reason, or for something trivial, then that would have been murder. But acting in defense of another person (or yourself) is, by definition
, not murder. If I kill somebody who's robbing my house or is actively trying to kill me (or somebody else), then that is never murder.
(If they're running away and I shoot them in the back, then THAT is murder, but that's not what Riker was doing.)