Honestly your very last pic does not look that bad but hard to tell w/ wavy water.
I have once had a mag that looked like it was trying to split during treatment, and it was a serious up and down bout, just like you thought it was gone, then looked pretty good, back and forth.
There was one period where it looked so much like splitting I actually thought of helping it manually, thinking maybe I'd at least have one of the splits survive, because it looked like one side was fine and the other toast.
I wonder what would have happened, because that particular mag just one day went to mush, did not make it.
On this particular mag I did not have cipro on hand and at the ready, I fast shipped as soon as I saw deflation, and I think it was just too late.
Now I advise having it on hand for immediate treatment, I think time is of the essence once you see deflation.
I'm not sure if that is your case or not, and can't speak for what you are seeing, but no harm can be done trying till the end since it's in QT, I would not give up.