I would leave it unless it looks like its falling apart, if there is stuff coming out of its mouth, take it out. Usually when they start expelling waste like that they are goners.
I don't see how a snail spawn could have caused your BTA to get like that. I would do a water change and run some carbon if you haven't already. Skim heavy and keep the water good in order for a full bounce back from the anemone.
If something happens at work.... well, I guess something happens. Don't take it out if it is still alive though. Leave him be.
If it does die while you're away, make sure to check as soon as you are home from work.. and take whatever measures necessary at that point.
Good luck,
Scott