HO BOY! I was in an angsty mood and this idea has been sitting in my drafts so here's my take on what I think will happen in the finale. Hope y'all enjoy!

She should have trusted her gut, she curses as Marcus shouts at her from the passenger seat to slow down. Watson speeds down the sidewalk towards Brooklyn Bridge as quickly as she possibly can without compromising their safety. She'd parted ways with Sherlock not even an hour. She and Marcus had gone to arrest Reichenbach but when he wasn't where Sherlock said he would be, she had a ridiculous gut feeling. She didn't even explain before she pulled away from Odker. It was only when she managed to subside the initial panic that surged through her body, that she explained her thoughts to the detective.

He is going to confront Reichenbach. She just knows it.

Memories flash through her mind rapidly. How he'd tortured Moran, how he'd nearly killed Oscar Rankin before relapsing. She swallows the guilt that follows the two, fingers gripping the wheel tighter. He'd come excruciatingly close so of course when they got the call from Kitty that someone was watching her and Archie, followed by similar reports from the captain and Bell himself. It was when she noticed the same car trailing them, she thinks that broke his resolve.

McNally had threatened them all in the name of Reichenbach. Watson grinds her teeth at the thought of him hurting any of their family. They'd tried absolutely everything. This damn man had even Moriarty ducking away. He'd known about her daughter. He'd known where she was, who she was with. It was enough to keep Jamie at a distance. Everyone had come up with nobody that would be able to stop him. She'd even suggested retreating back to London, coming up with a game plan before attacking once more.

Finally, they'd caught a break. Actually, more like Kitty caught the man watching Archie at daycare and coerced a confession out of him. It was enough to warrant an arrest on charges of stalking. Surely enough three more men came in, admitting to following her, Bell, and Gregson for Reichenbach as well. She should have known they'd submitted too easily. Only a mention of Sherlock's father and the wealth associated with his family would have crumbled the strongest resolve in criminals.

Sherlock's desperation to protect them extends beyond logical reason.

As they pull up she searches wildly for any sign of either of the men. She climbs out of the car and that's when she spots Sherlock.

Her heart falls to her stomach when she notices he's standing on the other side of the railing. "Sherlock!" She can barely hear her own scream over her heart pounding in her ears. She wants to believe that this is another dumb method to help clear his head, he talks to a porcelain bust and owns his own hive of bees on their own roof so it wouldn't be far fetched. For god sakes he faked out getting shot once just to introduce a case. She pleads with the universe that this is the case. She tries not to think about how she saw Reichenbach's car but has yet to spot the man. But when his eyes meet hers, she knows what she feared had come to fruition.

She can't make out what Marcus is saying. Her eyes can't leave his, they're filled with so much sadness. Against the protests behind her, she goes up to him. "Sherlock." She whispers this time. Carefully, to keep his balance he turns to face her. She wants to grab him by the jacket and pull him over to safety.

"I can't protect them." He whispers sadly. In that moment she wants to yell at him. They'd had him for stalking charges. Surely Moriarty would've taken care of the rest. She's done more for lesser threats. With the "alliance" her and Sherlock have Reichenbach would've been gone. Again, she swallows the guilt. They have so much blood on their hands. "I can't protect you."

"He's gone Sherlock." Her hand hovers between them. He's so averse to touch and the last thing she needs is to startle him right now.

"Reichenbach wasn't the only one. Ever since coming back to America you've come under constant threat. You came under threat because of me."

"We're always under threat."

"You shouldn't have to be."

"Neither should you." Finally her hand touches his cheek softly. "Sherlock come home. We've figured these people out before. We always come home. Come on,"

"I can't."

"Sherlock please." She hates how broken she sounds. Her words don't even sound like her own. His forehead dips down to touch hers. He closes his eyes just breathing in the moment.

"Do you trust me?" The question is absurd after all they've been through. Not once had she even considered anything but complete trust with him. Even during the rough patches she trusted him wholeheartedly.

"With my life."

"I will be back." The whisper is so soft she almost misses it. "I will find you again. This I promise you." She can't decipher the meaning behind the words. Only that he pulls away from her touch. His lips are cold as they press against her forehead. "I have never loved anyone as I do you, right now, in this moment." The words suspiciously feel like goodbye. Surely enough she feels his touch, his warmth abandon her completely.

It takes mere moments to recognize that he was falling. She reaches for him with a shout fingers barely missing as she's tugged away by another pair of arms. Marcus holds her to the ground to prevent her from going off the ledge as well. She tries to fight it. She has to help him. She glances down into the darkness but sees nothing. Not even a ripple of water marks his descent.

"Joan!" Marcus yells pulling her backwards still as she kicks and screams. "Joan please!" She can hear his voice break and it sounds so final. "He's gone."

With those words all the fight in her body crumbles. It all falls away so easily. Her legs no longer want to hold her and her heels she's normally so sure in feel unfamiliar. She lets herself lean on Marcus. She can't help the sob that escapes her throat. His words just keep echoing in her mind.

'I will find you again.'