A/N: This chapter's T-rated mashup (with a sprinkling of other TLD dialogue mixed in):

S4/TLD Just tell me when to cough. / I've seen healthier people on the slab.

S3/HLV How dare you throw away the beautiful gifts you were born with! / And how dare you betray the love of your friends? Say you're sorry.

Molly shook her head as she helped Sherlock settle himself onto the gurney. He refused to lie down no matter how much she urged him to. "I don't understand why you're doing this to yourself, Sherlock, I really don't. Do you honestly think Mary would want -"

"Actually I'm doing exactly what Mary would want," Sherlock cut in. He huddled in his coat, staring down at his feet, feeling the movement of the ambulance as it took them both closer to his confrontation with Culverton Smith, Secret Serial Killer. "Not only that, I'm doing exactly what she asked me to do."

"She asked you to destroy yourself, to throw away the beautiful gifts you were born with?" Molly demanded in rising fury. "To betray the love of your friends and, and put yourself through hell?"

"No, she asked me to save John Watson," Sherlock corrected her. Molly's eyes widened as he went on. "She left me a DVD," he explained. "Asked me to save him by putting myself in harm's way and yes, she literally told me to go to hell - where I am now, especially since you've declined to tell me when to cough," he added, aiming for a lightness that was spoiled by a fit of hacking and coughing that brought Molly swiftly to his side. No ball-fondling was forthcoming, alas; instead, Molly whipped out a stethoscope and listened to his lungs and heart.

Neither of which, as she told him with concern roughening her voice, were properly doing their jobs. "Sherlock," she said once the examination was over and she'd urged him to lie back for the remainder of the journey, "there's no way Mary meant for you to to literally try to kill yourself. I know you feel guilty for how she...how she died-"

"Of course I feel guilty for how she died!" he shouted, struggling back to a sitting position in order to glare at her. "How could I not when it was entirely my fault? So yes, forgive me if I decided to honor her last request and save John from completely self-destructing!"

"Right, because it's so much better if you self-destruct instead!" Molly exclaimed hotly. "Sherlock, she said to save John, not destroy yourself! She had no idea how or when she was going to die, she didn't make that disk in order to extract some sort of beyond-the-grave revenge on you! She thought her past was going to catch up with her - and that's exactly what it did!" she added, jabbing her finger at Sherlock's chest as he opened his mouth in an attempt to interrupt her. "No! You don't get to talk, it's my turn!"

She waited until he'd closed his mouth again before going on. "Look, Sherlock, you might have talked yourself into believing this was the only way to save John, but for God's sake, he's in therapy, he's eventually going to find his own way past his guilt and anger, you have to trust in that!"

Her eyes glimmered with tears, and Sherlock realized how much of an emotional toll his actions were taking on her. She wasn't just angry; she was terrified for him, for his life.

Unbidden the words he'd spoken to Faith Smith sprang to mind: "Taking your own life." Interesting expression. Taking it from who? Once it's over, it's not you who'll miss it.

"I don't want to die." As soon as he spoke the words, he knew them to be true. He reached out, ignoring the trembling of his hand, and grasped Molly's fingers. They curled around his, holding tight, as he looked into her eyes. "I promise you that, Molly Hooper. I don't want to die, to destroy either myself or the 'beautiful gifts' I was born with. And yes, John is moving toward recovery but we both know it's not a smooth path with a foregone conclusion: therapy, recovery, relapse is the more usual model, isn't it?"

He waited for her small, silent nod before continuing. "I know that, right now, it seems like I'm being flippant and careless with my own life, but I'm not." He took a shuddering breath. "I told someone once that a person's death isn't something that just happens to them, that someone's - my - life isn't my own." Your own death is something that happens to everybody else. "Because of that I promise I'll - I'll keep my hands off it. Once I've saved John - and that bastard Smith is behind bars - I'll get myself cleaned up again, just as I have in the past."

"You promise."

It wasn't a question, but he nodded anyway. "I promise, Molly. I swear on my life. You're right about that much; Mary wouldn't have wanted me to kill myself to save John." He gave her a lopsided smile. "Unless of course it was by throwing myself in front of a bullet or pushing him out of the way of a moving vehicle. But no, not like this." He glanced down at his riddled forearm then back up at her. "Am I making any sense at all?"

She nodded, blinked back tears and squeezed his hands. "You are. You promised you aren't actually trying to kill yourself and, God help me, I believe you." She frowned. "That doesn't mean I haven't seen healthier people on the slab, mind you."

"Yeah but, to be fair, you work with murder victims. They tend to be quite young," he offered jokingly, but she wasn't quite ready to smile with him yet.

The ambulance came to a halt and he struggled to his feet, Molly's warm hand steadying him. He pressed a kiss to her forehead and allowed her to escort him to the door, where John was waiting for them. "Well?" he demanded. "How is he?"

Bluntly, as clinically as possible, Molly told him the truth - that if he kept taking what he was taking at the rate he was taking it, he was weeks away from dying.

What she kept to herself was the hope that Sherlock was telling the truth; that as soon as Culverton Smith was exposed as a murderer - and John had the chance to save his estranged friend - he would get his own mess of a life back together again.

End note: Many thanks to Ally on the sherlolly discord for reading this over for me!