I can usually tell if a polyp is fixing to make it's final curtain call if the pods start paying it a lot of attention. I have a polyp that I glued onto a rock about two weeks ago that still hasn't reopened. I think it's a goner; but so far the pods have ignored it, and my pods are ruthless towards any coral that is dying.
If it was mine, I'd leave it alone. If it's bad, the pods will remove it for me. Or you could cruch it's base with the tweezers and remove it. If you do, be sure that you wash the tweezers well with hot water and soap soon after you finish.
Zoo Goo is nasty stuff.