That's an extreme case..but it has happened. Aside from this, feeding would be an issue because you'd HAVE to put at least one in another enclosure and some won't eat outside of their own 'home'. Then if you put them back together too soon, one may still be in feed mode and tag and wrap the other, which is what probably happened to the ones in the pic.
Aside from the main issue of them hurting each other, you also run the chance of both being sick or get an infection. And if one gets it, the other one will. Then you'll have two sick animals instead of one. Plus there's the point of not knowing who's pee'd or poo'd. It may be in the cage, but who does it belong to?
In all, never house two together (although there are very few who do well with others) for safety and health reason. Your animals will be much happier by themselves.