What are you talking about?
Innocents must help the sheriff before the murderer kills them, innocents who witness a murder must tell the sheriff so the sheriff and the other innocents will not be troubled by the players around them
Imagine if someone witness a murder in real life what will they do? Tell the police about it or just run away and dont tell the police about it like nothing happend?
The Answer is either of the but they must tell the police about it.
Just like in the game, some innocents tell the sheriff about the murder some of these innocents gets killed while trying to expose the murderer to the other players.