She lets him go, mostly because he already half-wrenched himself out of her grip when he moved over toward the tree, and crosses her arms.

"Somebody has to help them." And if she doesn't, then she'll have to live with the guilt when they die. Beth can't stand around, knowing she could help them, even just a little bit, and let things happen how they will. "But this isn't about me. I'm not the one who's sick."