The idea of a private military contractor taking on the Russian Military is a complete joke. If mercenaries there are anything like here they're getting paid way more than their rank and file counterparts. Regular soldiers won't necessarily have endless amounts of sympathy for these guys just because they're fed up with this or that about the conditions there. Frankly I have wondered from the start if Putin knew private contractors are usually trouble and decided to use them as extremely expensive cannon fodder to keep the regular military from taking such a huge hit from all the fighting.