I have read that what we interpret as cute, bonded, and loving, is actually dominance, bullying,and stalking.I have had two female Russians housed indoors in the same enclosure for 8 years and definitely have noticed mounting, biting, and other signs of dominance between them. Luckily, it never seems to get out of hand and there have never been any injuries. I am careful to spread out their food so both can feed separately. I have two separate hides, but they frequently use the same one and coexist nicely. They seem to tolerate each other, probably better than humans would under the same circumstances.
They don't want to hang out, cuddle, or share time with one another. They want the other one out of their space. So they follow each other around, cuddle, and seemingly seek each other out to keep nasty tabs on, stalk, and terrorize each other. Some doesn't seem harmful--what's the harm with a head bob or shoulder bump or a cuddle, right?
But... Think of someone shouting obscenities, sending you dagger looks, invading your space (sitting too close, popping up where u are when all u want is some alone time, etc) in hopes of driving you away (but where can you go?)...how would you feel? And how would you feel on the other side, having some unwanted visitor always in your house, eating your food, and taking up your space? It would wear on you too! There may not be blows exchanged between you two, but you will feel stressed, hounded, upset. And just cuz you haven't stepped it up a notch yet doesn't mean you couldn't at any time...
Keeping them together is cruel, even if no blood is shed (yet). Why put them both thru that (the hounded who can't get away, and hounded who's like, "What are u doing in my home--get out already!!") Not to mention the risk that it could become physically dangerous or even deadly?
Separate them out of kindness...not just physical safety. I think we can all agree emotional stress is just as harmful in the long run.