Always, when Rey leaves, he looks at her retreating back and acknowledges, if only to himself, that she may not return. Even if she had remained in the Thaig, that might have been true. There was plenty to guard, but the Deep Roads were hardly free from hazard; cave-ins, magma-flow, darkspawn, and numerous other subterranean dangers had become commonplace. Perhaps that was paranoia speaking; there could be little more capable of avoiding the unseen dangers than a Jedi, and Rey was that. Forgive him his fretting then:

Despite all strictures to the contrary, Rey is precious to him.

And, whenever she returns, they have made a ritual of it; she bends down for him, and he takes her by the shoulders, to see that she is whole. And she usually is. But not today, when she is staying in, for once.

"You're very intent, tonight," Obi-Wan remarks, from his seat near the door. He is watching the common space outside their door, sensing the tenor and health of the community, as he always does, "What are you working on?"