I have a photo just like this with a Naso sticking out of a crocea. Clam did fine, Naso did not. Took 2 days to get the tang out, I was worried about damaging the clam by yanking it out.

That's really sad. I've heard stories of this as well and it's just an unfortunate aquarium accident that probably never happens in the wild. I know how attached I am to my yellow tang and that I'd be really upset, so my condolensces go out. RIP!

I had similar incident with Yellow Tang and a crocea. The Tang went completely stiff. I slowly pried open the clam to release the fish - it took over an hour. The fish sunk to the bottom with lacerations (the clam had shut just in front of the fish's eyes). Fish survived. Clam survived but ended up dying about 4-5 weeks later for unknown causes. I've learned since that jetting cold water with a turkey baster will relax the clam and allow it to release a stuck fish.

This happened to my blue tang once as well. The clam which reacted to the "nibbling" was a T. crocea and it shut pretty darn tight. The tang had no chance at all, sad to see another occurrence of a "murderous clam".