Here in Europe the 4 months she was at would be somewhere mid to end of the trial period, during which you can be let go without having to provide a reason on relatively short notice. This is also pretty much the only chance you get to easily let go a specific individual - so if there are indications it’ll not work out doing just that is a good idea.

But having that done by arbitrary HR drones is just crazy, and obviously you’ll be entitled to unemployment benefits or other social benefits after that.