It takes a second, then a sigh (relief and exasperation and full of finally), but River hugs back. His guilt surges and her stomach turns two degrees counter clockwise but she still hugs him back. Clings, even, grabbing fistfulls of cloth at his back like it'll make a difference in whether he disappears or not.

"Everything shifts and I can't see, duì bu qǐ," and she can't tell if she's apologizing for not finding him sooner or for thinking he wasn't really him.

Honestly, it's probably both.