He talks to her as soon as he sees the light-the doorway where she's standing. He catches her up on everything he can think of, including that he has a playlist set up on a laptop for her. When he leaves, he'll start it and she'll stay caught up. He contacted her loved ones in Mystic Falls, he has resources being sent to Bonnie to help her determine if there is a spell capable of such a thing. He apologizes, but he doesn't trust another witch with the knowledge of her coma. he begins to apologize, but she shakes her head. He stops. She thanks him for it, and thanks him for sending Caroline. He brushes it off, it's nothing. He wants to tell her he wishes he could do more, but he knows that'll only hurt both of them. He tries to be unselfish with Elena, and so he keeps his pain to himself.
She carefully manages to form a doorway between their minds, and he holds onto her as they get moved into inky darkness. She clutches at him, she doesn't like the dark. It was already terrifying in her mind, she can't imagine it being any better than Elijah's. He calms her down. They're not stuck or lost, they're where they need to be. He asks in a quiet voice what he needs to think of when forming the bones of his mind palace.
She closes her eyes and tells him that he needs to do the same.
He needs to think of architecture he likes, why he likes it. He needs to think of favorite places and safe places, sacred places and hiding places. The result should be something solid he can feel in his mind, not to think about it too hard. He shouldn't try to form anything, he just needs to think of the things she mentioned. She feels the air shift and his grip on her hand tighten for a moment. She opens a hesitant eye, seeing the last of memory-like smoke place itself where it needs to be.
She squeezes his hand and tells him to open his eyes.
She's sure it has more meaning to him, but she can pick out bits and pieces of periods and styles in the mind palace. Hers was formed from what she knew. His almost reminds her of manors and vacation homes for some reason, it's gorgeous gray stone. More castle than anything, he'd admit if she asked. She doesn't, and they just spend a few minutes sitting, admiring the exterior of his mind palace.