Doc,
If I flag a post, I immediately email other HL's asking they process.
Or, I email 1st to see who's online, then I flag and let them decide.
If the post is clearly a rule vio, especially a personal attack, profanity or spam, and nobody replies that they will process, in other words, I am alone, I'll do it myself.
These same HL's on multiple boards do same with me.
It's an agreement we reached years ago and it works.