Why doesn't Russia make a devil's deal with China to backstab NK, launch a surprise attack, and carve up the territory between them? With some nebulous hand-wa

Why doesn't Russia make a devil's deal with China to backstab NK, launch a surprise attack, and carve up the territory between them? With some nebulous hand-waving about their rhetoric leading to "global nuclear destabilization" or somesuch (even if it's clear from the lack of troop movements that the rhetoric is just rhetoric). They wouldn't have to deal with a popular rebellion in Iraq/Afghanistan, just send the people a little bit of food and start modernizing the countryside and they will be hailed as liberators. Best to do it now, before they have to deal with another nuke club member in their backyard that's a total wild card... And if Seoul gets demolished, South Korea isn't their ally, so that's Somebody Else's Problem.