This is your survival instinct, i.e. your ego, kicking in to keep you from harm.  

That can range from a spike in input costs such as sudden rise in the price of oil or corn to a shift in sentiment that could generate new legislation that either aides or harms a company. 

The Saudis at times have increased or held steady oil production to harm the Iranians and they could be doing it now, but for what particular reason right now?  

Turnover is already a given, so there is no harm as long as you can re-fill units quickly.

What is the harm of him exploring all of the options available to him?

He can not win so he is just going to do more harm to himself the longer he plays his game.  

Have a qualified person come and check it for residue as it can be extremely harmful to health of new tenants.

I certainly don't think I'm unique when it comes to things like that...I remember from another thread that you think babies should be forced to fend for themselves when necessary, so maybe you aren't typical, but I think most people are compassionate and will do their best not to harm other human beings, even without consequences.

BBB and report this clown to in an attempt to keep others out of harms way.

Why not just sit down with her (if you can get her) and explain that you know she is in a bad situation, but you have to move forward,,the problem being if you evict her, it will be much harder for her to find a future place to live.Tell her if you can work out some arrangement, like giving her 2 weeks go get out, you will go along with it and take that amount out of the deposit (please tell me you have a deposit),,,If you approach them that you know that they have a problem,and you don't really want to harm them, instead of 'attacking' you might be shocked at how SOME people will react (others will just see it as another way to rip you off)After that if they haven't lived up to their end of the deal, throw them out the door,,you can even say in court that you tried to help, and wanted to keep from evicting them, but they gave you no choice (in case they play the "we didn't know it was this serious" card)