“Are you certain that’s what you want?” she panted, tilting her face up toward his.
The Doctor’s voice was surprisingly gentle, his breath tickling her forehead. “You’re running out of oxygen and you’re not thinking clearly. Let’s just get out of here, alright?”
The understanding clicked into place just a beat slower than it ought to have –sufficient proof that he was right. Clara calmed herself, trying to pull her traitorous lower body back under control. “Fair enough.”
She gripped the end of the screwdriver and withdrew it. Within a few minutes, she had worked it back down and pointed it toward (what she had to guess was) the seam of the casket. It was short work to loosen the hinges enough that the Doctor could push the lid off of them. As she tumbled out, Clara took in enormous lungfuls of air. The room without, a smallish chapel by the looks of it, was nearly as dark as it had been inside the long, narrow box. But it still felt like a miracle just to see the outlines of her hands in front of her face, again.
The Doctor rose slowly and stiffly, reminding her vaguely of an old-timey vampire film. He climbed out with his back to her, brushing off the front of his jacket.
“Doctor…” She didn’t have the slightest idea what to say but something needed saying, didn’t it?
“Oxygen deprivation has been known to have certain..erm… physiological effects on the body. Even Time Lords aren’t necessarily fully immune...” He started, sounding for all the world like that science teacher at Uni who put the whole class to sleep during every lecture.