Sirda is driving me crazy!

Okay, I am re-typing this because I just read through what I wrote before and realized that it made no sense.

Let me go back a week.  Scooter was found to have crystals in his urine, so they gave me prescription food.  Well, it is about impossible to feed both of my cats separately, so I just put out the prescription food and took away the old food.  Well, apprently this didn't do so well with Sidra.  I get home Thursday evening to find about 6 or 7 vomit spots, and one diarrhea spot.  So I lock Sidra in the bathroom put a cat box in there for her, and her old food, plus water.  I cleaned up the vomit and diarrhea as best as I could with paper towels, I don't have anything to clean the carpet.  I then went to the seminar I wanted to go to, then to Walmart to get carpet cleaner.  I go home, and clean the diarrhea mess with the cleaner.  Then I looked in the bathroom and saw that there was no new diarrhea or vomit.  So I let her out, and just put out he old food for them to eat.

Well, yesterday (Friday) I just thougth that maybe it was because I switched the food too fast.  So I took a tiny mixture of food, like 1/4 prescription food, and 3/4 old food.  It was okay for a day, then this morning I wake up to find 3 piles of diarrhea on the rug.  I was upset by this.  I lock her back in the bathroom, with her old food, water, and a cat box again.  She was very unhappy and meowed and meowed.  I then cleaned up the diarrhea with the carpet cleaner.  And of course, the carpet cleaner is not perfect, after I clean as best as I can with the foaming stuff, and a damp rag, I can still smell it in the carpet if I put my nose to it, but you can't see that it was there.

I go back into the bathroom, and notice no new diarrhea.  So I let her out and watch her, and she runs straight to that area of the carpet, and starts to diarrhea again!  I grabbed her in the act and throw her back in the bathroom and then have another spot of diarrhea to clean up. 

Ugh, I sm SICK of cleaning up diarrhea.  Now she has been locked in the bathroom for half of the day, and she still has diarrhea.  But I think she is running empty.  And while in the bathroom she uses the cat box very well.

So my question is: will she continue to use that area of the rug to deficate from now on?  Am I doomed to that?  Will Scooter start using it?  I am moving in a month and want some of my security deposit back and they shampoo the carpet whenever a tenent moves out.  But if Sidra thinks that the carpet in that area is her new "cat box" what am I supposed to do?  Is it si good idea to maybe rent a carpet shampooer from Lowes to clean that area theroughly, or will she just continue to use that area, making that a waste of money?  I just am so disgusted to think that there is still poop there, that is impossible to clean up with a wash cloth and a bucket of water, and a jar of foaming carpet cleaner.  The poop now is just deeper in the rug, and it is really gross to think about it.  I want it gone!  What should I do?