If they are in Rostov, they have left Ukraine and are building an enclave for themselves in Russia. Surreal, but could actually work for some time.
That is the area where they are reported to have been seen in numbers
If Russia tries to attack them in that position, it will open their backs to the Ukrainian forces.
Will they open fire inside a city on their own people? Thats the question.
A recent Nebula Podcast talked about the Wagner Group and how they are stacked with unfree Russians. Life sentences convicts turned into soldiers and foreign fighters are a big part of that group. So it's very hard to tell what they would consider "own people".
Yeah, that is another worthy point.