He asked all those at the Wake to vacate the chapel as he wanted a last hour alone with her before they closed the coffin. After the last one of them had filed out, he shut the doors and returned to the the catafalque. 
“Why did you have to leave me? You know I can’t live without you. I’d do anything in my power to trade places with you. And right now, I only have one thing left in my power”. 
He slipped a razor blade from his jacket pocket and ran it deep across his veins. He then climbed awkwardly into the coffin and lay exsanguinating on her corpse. His lips kissed her bloodless ones and he shut his eyes in expectation of an eternity of kisses ahead. 
*
She felt like she was being crushed. Her eyes bolted open. Her eyes weren’t focusing, but she could make out light so she realised she hadn’t been buried alive. Which was odd, because her last memory had been the cab of the articulated truck bearing down on her in her car and her apprehension of immanent death.
Yet here she was, still sensate and though she was labouring beneath a deadweight, her own bones were not hurting her. She blinked her eyes rapidly to try and shake clear their mists and render her some acuity of vision. Somebody was lying on top of her, but he wasn’t dressed like the lorry driver. Moreover, she herself was lying prone, so she wasn’t in her car. She inched her fingers out to the side of her and hit wood. 
With great effort she managed to shift the torso enough that she was able to flex her own limbs. Finally her eyes were settling down into clarity. She saw that her dress was covered in blood, but before a scream could emerge from her throat, she discerned that rather than the grey trouser suit she had been wearing in the car, she appeared to be clad in her wedding dress. 
Didn’t matter about creases now, since it was covered in blood, so she flexed and wiggled some more trying to free herself. And then she was confronted with the identity of her encumbrance. it was her husband. Now she screamed. Was she in some sort of inverted hellish place where she had lived but he was dead? 
She finally managed to scramble out of the coffin. Coffin, wedding dress, looking round the decor of a Chapel of Rest. So she had been dead and about to be buried she reasoned. And yet here she was very much alive, or at the bare minimum travelling out of her body. She rapped her ribcage, seemed substantial and fleshy enough. She looked down on the floor and saw the copious blood drops. She also clocked the razor blade. Well they had always said that whichever of therm died first would leave the other so bereft that they would follow immediately after. A mushy, mawkish lover’s suicide pact which by the look of it he had only gone and carried through with. Touching in some ways. Foolish in others. More’s the pity. She couldn’t quite fathom the turn of events, but his sacrifice had somehow resurrected her. 

She supposed she should reciprocate with a sacrifice. She picked up the razor blade, it could commingle their blood. Requite them once again. But the thought of dragging the blade across her wrists made her feel queasy and she had to steady herself by grabbing on to the coffin. There was no guarantee they would be reunited. After all his act of self-abnegation had only served to revivify her. What if laying down her life reanimated him? They would never be together, but locked into some horrendous continuum of swapping places but never able to coincide? The thought was too horrible to bear. She wondered if her grey trouser suit was still salvageable and if she could still make that business power meeting…