A/N: I wrote this for a "What If" ask on Tumblr for jediserenity82. Instead of choosing a "what if" scenario for one of my existing stories, I decided to write a one-shot about what could have happened in Mass Effect 3 if BioWare had actually cared about Thane and the players who'd romanced him, and let him live and join Shepard for her fight with the Reapers. So, this is my version - my headcanon - of the events of the Cerberus coup on the Citadel. I refuse to accept the fate the BW writers/producers chose for Thane.

As far back as he could remember, Thane had never been a deep sleeper. Even without his training and the strict lessons installed in him from a young age that ignorance of your surroundings, whether asleep or not, was a good way to get killed, he'd never been fond of succumbing to mindless, unconscious inactivity.

It was no surprise, then, that the worst side effect, as far as he was concerned, of the medications he was forced to take while recovering from his lung transplant, was the fundamental change in his sleeping patterns. The drugs knocked him out for hours at a time, and he detested the feeling of fuzzy-brained confusion and the loss of hours of alert awareness every time he woke.

As soon as the worst was over and he was offered a choice, he declined the strong painkillers that induced that state of unconsciousness. The days were longer, Shepard's absence felt more acute than ever, but at least his mind was clear of the fog of those last few months.

Now, lying in his bed or sitting in the lobby, waiting for the minutes, the hours, the days to tick by until he finished his treatment and could join his siha on her ship, he could hear, smell, and see everything that happened around him: the nurses hurrying to attend to the wounded; the doctors rushing to the bedside of the sick when their conditions changed for the worse; the visitors walking through the hallways, searching with hushed whispers for their loved ones, hoping they could still find them alive.

He'd gotten used to the noise; the soft clank of a metal tray against a cart at dinner time, the footsteps of the workers as they went on their business, the frantic shouts in the corridor when new patients came in and Huerta Memorial exploded into an anxious beehive of activity.

This evening, the place was rather quiet and, after his physical therapy, he chose to sit in his favorite place, an armchair by the large, wall-to-ceiling windows in the entrance hall. The view was breathtaking, but he barely saw it; his mind was far away, in Shepard's cabin, sitting on her couch with her on his lap, or lying in her bed with her body next to him, dreaming of the future he'd never thought he would get to have.

He could almost taste her last kiss on his lips, and he closed his eyes as his memories overtook his every sense, the outside world melting away into an inconsequential fleck of dust on the horizon.

Until the elevator door blew open and the first Cerberus commandos burst into the room.

~ooo~

Thane's first thought once he'd managed to slip away from his pursuers was his son.

He opened a comm channel to raise Kolyat, but there was no answer. The silence was not entirely unusual; Kolyat was still in his C-Sec training, which sometimes meant going on long stakeouts with his supervisor, and Corleus was nothing but a hardcore stickler for following protocol and not answering personal calls while on duty. Still, if there ever was an extenuating circumstance to relax those strict standards, the Citadel being under attack should have been it, so Thane tried and tried again, first requesting a voice call, then a text message.

The results were the same.

His eyelids fluttering, he tamped down the anxiety rising in the pit of his stomach, inhaled a large lungful of air and blew it out slowly through his lips, then put in a call to Bailey.

This time, there was a reply. "Thane?" Bailey said. His voice was strained, but at least he was alive and functioning. "Are you all right?"

"Yes. Do you have any news about Kolyat?"

There was a small pause at the other end of the line. It couldn't have been more than a few seconds, but to Thane, it felt like an eternity.

"Looks like he's out on patrol with Corleus. Civilian neighborhood, Bachjret Ward. Shouldn't have much Cerberus presence. Corleus is good; he'll keep him safe. I wouldn't worry too much."

The knot in Thane's shoulders relaxed and he dipped his head in silent prayer. "Thank you, Commander. I'll go and—"

"Shepard's on the station," Bailey said. Thane's head snapped up, his eyes opened wide. "She's gone to C-Sec headquarters to protect the salarian councilor. He was supposed to meet the executor today; he's probably still in his office."

"I'm on my way. Please let her know that I'll join her there."

"Will do."

~ooo~

Thane flattened his back against the wall and listened, waiting for the heavy footfalls of the Cerberus troops to die down in the distance. Shots were still being fired, but they were getting farther away now, and he peered around the corner, chancing a look at the walkway beyond. The ground was littered with dead bodies and charred rubble, but there was no movement, no enemy combatants left to stand between him and his destination.

He took a deep breath. Even with the unnatural stillness in the air, the path to C-Sec headquarters was going to be a challenge. It was long and wide and dangerously exposed, and every fiber in his body was telling him to take it slow, find a different way, but there was no different way, and there was no time.

His eyes closed for a moment as he said a short prayer to Amonkira, and then he ran.

~ooo~

It was strange, using his legs and heart and lungs out in the real world now, in an actual combat situation, instead of the closed, controlled environment of his self-induced training regimen in the hospital. His body didn't respond quite as well yet as it used to, but he could breathe without choking (albeit with a certain level of discomfort) after the exertion of running and diving into cover and jumping over barricades. That was not the only good news: despite his less than perfect physical shape, the number of dead Cerberus soldiers on the far side of the room was welcome proof that, as far as his biotics and his aim were concerned, he was still as deadly and efficient as ever.

Nevertheless, there was no reason to risk running into any more troops before he reached the executor's office. Shepard was waiting for him, counting on his assistance, and he was not going to let her down. He pocketed a few thermal clips and picked up another gun from the floor, snapped it into his holster, and searched the premises until he found a ceiling vent. He removed the gate, pulled himself up through the hole, and climbed in.

~ooo~

Cerberus was everywhere.

Thane wondered, as he slowly made his way in the vents, when exactly The Illusive Man's organization had gotten so big. He remembered all the missions and errands that unpleasant man had sent them on while Shepard had been working with him—all those insignificant tasks and rescue missions that could have been accomplished simply by deploying a fraction of these troops.

Judging by the sound of gunfire reverberating through the metal tunnels he was crawling in, Shepard and her team were severely diminishing those numbers, at least. He hoped their efforts would be enough to keep the enemy away from the salarian councilor until he got there—which, if the map on his omni-tool was correct, should be right about... now.

He peered through the holes in the steel grate and listened. The room appeared to be empty, but he still took care to remove the vent cover as quietly as he could before he dropped down from the ceiling.

At first, all he saw was the devastation: bodies, pools of blood, burn marks, and equipment blown into jagged little pieces everywhere. He crept along the aisles of desks, and stopped, stooping down when he heard something.

His heart missed a beat when he recognized Shepard's voice, strong and authoritative, ordering an unseen assailant to stand down.

"Three against one. It's over, pal," she said.

Thane took a silent step forward. He could see everything now: Shepard, Garrus, and an unknown Alliance soldier at one end of the room, a man in black leather armor just in front of him, and the councilor in between.

The man raised a hand, his palm glowing with the beginnings of some kind of biotic energy. "No. Now it's fun."

Whatever that ball of energy was, Thane was not going to let it grow and assert its power. With practiced ease, he cocked his gun and aimed it at the assailant's head.

Under normal circumstances, he would have pulled the trigger in the same motion, but this time, he hesitated, waiting for Shepard to give the sign whether she needed his target alive. A dead man could not talk, after all.

His hesitation turned out to be a mistake; the man spun around, faster than Thane would have expected, and tried to knock the gun out of his hand. The pistol wavered for a moment, but Thane held it tight, and snapped it onto his belt even as he dodged a fist directed at his throat. He met the next blow with his forearm, and followed up with a strike of his own.

The next few seconds were nothing but a blur of punches and blocks as each fought to gain the upper hand. His adversary was good; he'd obviously had some excellent close-combat training, as he could deflect most of Thane's blows, and almost got in a few hits himself.

It took a spinning side kick to the man's sternum to make him stagger back, giving Thane the opportunity to launch him across the room with a powerful biotic throw. The assassin landed on the floor, sprawled in a limp crumple, and Thane took his chance to snatch the gun from his belt and aim. He could hear a series of swift clicks from behind as Shepard and her team lifted their own weapons as well. Unfortunately, there was nothing to fire on; their target had activated his cloak and disappeared from sight.

Thane listened, his large eyes darting around him, looking for the tell-tale shimmer of a cloaked figure. He didn't have to wait long; the man materialized right behind his back, ready to strike. Thane whirled around and bent down just in time, narrowly escaping a sharp blade aimed at his torso. He tried to sweep his adversary's feet out from under him, but the assassin jumped up, avoiding another fall, and lunged forward with his sword.

Thane didn't have time to dodge the full brunt of the attack. He shifted, raising his forearm, denying the blade a clear path to his heart, but couldn't avoid a slice clear across his arm and a searing cut skidding down along his side. Instinctively, he pressed his fingers into the wound over his ribs as his blood gushed forth, his eyes meeting Shepard's horrified stare for a moment before flicking back at the assassin, just in time to avoid another blow.

"Thane," he heard Shepard gasp.

From the corner of his eye, he could see his siha and her companions raise their weapons, and he ducked, giving them the chance to fire at their mark. The man staggered, the blade faltering in his hand as the shots rippled across his barrier.

Ignoring the blood trickling out of his arm, Thane lifted his gun and fired as well. The barrier held, but it was obviously weakening under the barrage of their concentrated attack, and the assassin snarled, an annoyed look flickering across his face. With a growl, he snapped his sword to the holster on his back, took off running, and jumped down from the balcony.

Shepard and her team raced after him. Still holding his side with one hand, Thane joined the chase, sending a volley of gunfire into the back of the assassin, but it was too late. The man disappeared, riding the top of an aircar that must have been conveniently parked just out of sight.

Thane's gun slipped out of his grasp as his knees gave out and he collapsed onto the floor. His vision blurred, and he closed his eyes, but he could still hear and smell Shepard as she rushed to his side and began smearing medi-gel into his wounds.

He put his hand over hers, and squeezed it gently. "I'm fine. Go after him."

She'd taken off her gloves, and he could feel her warmth and a slight quiver in her fingers as she finished administering the medication without a word. The pain was subsiding, and the bleeding had slowed down to a trickle, and he opened his eyes, locked them onto her face.

She gave him a pleading smile. "Stay awake. Don't leave me."

"I'll… do my best."

Her lips trembled as she gave him a nod. She swallowed, schooled her features into that commander mask he'd gotten so used to during his time on the Normandy, and tapped the communicator in her ear. "Bailey, send immediate medical help to the executor's office. Thane's been seriously hurt."

"What's going on?"

"Udina's staging a coup. He almost got Councilor Valern killed, and he has the other councilors with him."

"Dammit. They're going to a shuttle pad on the Presidium. "

Shepard stood up. Her eyes flicked over to the salarian councilor. "Please stay with him until help arrives. Try to keep him alert."

She cast one last look at Thane, gave a signal to her teammates to follow her, and took off running.

Thane watched her until she jumped over the balustrade and disappeared from sight. His eyelids felt heavy, but he tried to keep them open, and forced himself to listen to the salarian's voice as he began telling him some ancient tale.

He lost the battle and fell into a dreamless sleep before the medical personnel arrived.

~ooo~

Thane woke up to warm fingers stroking a gentle path across his forehead. He smiled, looked up into Shepard's blue eyes, and took her hand to press a soft kiss to her palm. "Siha."

"How do you feel?"

He glanced down at his body, and lifted the blanket to take stock of his injuries. He'd been patched up, his arm and his torso covered in fresh bandages now. The movement hurt a bit, and being back in a hospital bed was more than a little disappointing, but at least he was still alive and breathing, and that certainly counted for something. "I'm fine. What happened?"

Shepard's face darkened, and her lips pulled down in a frown. "You lost a lot of blood. Almost didn't make it. The surgeons had to put a lot of stitches in to hold you together. Thank goodness Kolyat was here to give blood for your transfusion. Not many drell on the station, you know."

Thane tried to sit up, but the pain convinced him to drop back onto his pillow. "How is he? Is he all right?"

Shepard smiled. "He's fine. He's going to get a special commendation from C-Sec for his heroics during the coup. Just ran out to get me some coffee."

Thane's gaze slid down her body. She was still in her armor, the metal scorched by weapons fire and stained by her enemies' blood, her eyes tired and sunken in from the worry and strain of this day. Or was it the previous day, even? He didn't know. She must have come and stayed by his side this whole time—as soon as she'd dealt with that treacherous human.

"What happened to Udina and the other councilors?" he asked.

Shepard shifted in her seat. "Udina's dead. The councilors are safe. Cerberus is gone, but I couldn't catch the assassin."

Her jaw clenched, and he reached up with his good arm to touch the palm of his hand to her cheek. "You'll get him later. And I'll be there to help. If you want."

Shepard's frown disappeared. "There's nothing I want more, Thane. As soon as the doctors declare you ready to leave, you're coming with me." Her face lit up with a grin, and she leaned closer, her eyes locked on his. "I hope you don't mind giving up your old room on the Normandy and moving into my cabin."

The corners of Thane's lips curled up in a smile. He grabbed the back of her neck and pulled her down into a kiss. "I think I'll manage."

She chuckled, pressed her mouth to his, then laid her head on his shoulder, her arm carefully draped across his chest.

When Kolyat arrived with her coffee—black, two teaspoons of sugar, as she'd requested—he found them both asleep, heads tilted together and arms wound around each other, unwilling to let the other go.