I read a fanfic some time ago where single trolls could grow so enormous, far beyond giants, that they filled entire buildings, sewer systems, even cities, making the cities their own sentient beings. Obviously, Minna will most likely not do something like that, that'd be silly, but this page might be hinting at something on a smaller scale. Have you noticed a weird thing about troll nests? They seem almost organic, like a xenomorph nest from Alien, or an area with spores in the Last of Us. In these stories, it pretty much makes sense. Xenomorphs are insectoid, insects makes hives, and cordyceps are fungi, they grow like plants.
But what about trolls? Sure, it could just be a sort of evolutionary isolation, to keep the nests warm, but that would be boring. What if the walls and "structures" of a troll nest are actually an entirely separate troll? We've kinda seen it before, the sjødraug who seems to have grown part of the road. Or what if this is a kind of Vætte? We know vætter keeps in caves, in the shadows, studying bypassers. We always assumed they just hid in the caves, but what if they actually filled the caves, essentially making the opening to the cave their mouths, waiting for innocents to walk close enough to be stabbed by limbs, and pulled inside the waiting gap?