DUDE! What in the world!!! Are you just gonna keep on pulling them out of there like clowns leaving a car?
As far as what their risk is.... well, they're not a Bobbit, so your fish are safe. I keep a catalog of things experts say in relation to different critters.... real experts, not forum hitchhiker guessers (which is what I am). Leslie Harris had this to say about Eunices in our tanks...
"The only way for you to know what it eats & how it gets along with the other critters in your tank is to watch it. Most of them don't get very large & are inoffensive scavengers or herbivores at their size. If you want to be proactive & get it out you'll need to bait it out."
and..
"Some reefers have seen their large eunicids feeding on snails, dead animals, corals, sponges, etc. Others have had large eunicids that only eat algae & detritus. Smaller specimens have different food preferences than the large ones. So like I said, it's really hard to predict what any particular one will do."
I wouldn't tear apart a tank to get them out unless you're pretty sure they're doing something harm. I would try to bait them out, which may take awhile to be successful. If you have a lot of them, I would suspect they aren't eating anything desirable, or you would have noticed things you like disappearing by now.