If just a slight Contact with the branch was enough to start corroding the dome to such an enormous extent, imagine what would happen if the thing got tall enough to imbedded its tip into the dome.
It, the dome, would slowly be corroded till there was nothing left.
Hypothetically speaking, if those spots marked on the map was talking about this blood stone, and at each other locations, a similar monstrosity was being built, Imagining when they all grew and attacked the dome as planned, they could only stand and watch the dome crumble without any resistance.
Who would want that? The dome crumbling meant they were bound to be killed by the demons outside. Surely even the bravest of brave would be plagued by that thought, so everyone shivered involuntarily. Coincidentally the old people had just arrived to see and hear what Alia had said about that disgusting tree. Their hearts plagued and horror took over their facial expressions.