Her presence comes over him alarmingly at first, something foreign in his mind, and he recoils from complacency as he has always done, fearing that this is part of the transformation, this feeling of contentment, that it will override him and he'll surrender.

But she is more powerful than his own toxic energy, and as soon as he recognizes her he lets down his defenses. "TARDIS," he murmurs, aftershocks of terror keeping his voice unsteady. "But I'm... I..."

It seems like he's reaching out to her from within the tree's stranglehold, clamped around him and trying to crush him before she can pull him out. But she reaches right through it; grasps right onto his arm. The wood cracks around her and crumbles into ash, falling away. As Johnny struggles toward her stabilizing presence, more of his prison disintigrates, until finally he's shed it completely and he's on his knees before her, gasping, gripping her hands.