[Although he's more or less used to the phasing by now there is a moment of cold, pulse-quickening panic — before it's been short bursts of solid matter, walls or trees or ceilings. This is so much more than that, more than he can hold his breath for and although the mechanics behind it are exactly the same, the length makes it difficult to remember that he's perfectly safe in this impenetrable darkness.
The grip on her hand might've tightened during their decent. He may be letting out a breath of relief once they come out into the small, self-contained room.
There isn't much room for freak-outs though, and now that the flashlight actually has some space to illuminate his focus is very easily drawn away from the lingering panic. Brows furrowed in concentration he lets the light slowly wash over the room, taking in the preparations she's made. He tips his head back some to take in the construction of the ceiling they just came down through, assessing the structural safety of this hole in the ground. She's right, it won't make it into any engineering journals anytime soon, but in a place like this...]