Because Shepard isn't the only one with charm/intimidate options. Garrus+Shepard friendship.
"Shepard," Garrus nodded as he waltzed through the door to her quarters, ignoring the surprised look on her face. She made her way into the batteries unannounced all the time; it was only fair to return the favor.
"Garrus. I didn't think you'd still be on the ship," She replied, smooth as ever. The initial shock had given way to that cool professional tone that she used on their adversaries. She was no fool, and was ready to counter whatever it was he had to say. It was likely she had rehearsed—but then, so had he.
"We need to talk." Straight to the point—she wouldn't expect that.
A moment of silence, and then, "There is nothing to talk about. We're on the Citadel, and everyone is leaving. Including you. Get off the ship."
"No."
Shepard stared at him, eyes fixed on his. He knew this technique, and wasn't about to stand down. His commander was blind, and he intended to make her see.
"Vakarian, I will ask you one more time. Get the hell off of my ship."
"I don't think it classifies as being your ship anymore, Commander," He sniped, matching her sarcasm. "The Alliance will take possession of it the moment you're in cuffs."
Glaring, she held up her arms. "And you don't see any on me, do you? I'm still in charge. And I'm not going to ask—"
"They're considering execution." One look at her face, and he knew he had gotten through. Her eyes widened, and her mouth parted slightly—a human gesture of surprise.
It was silent for almost an entire minute, Shepard staring at the wall behind him. Finally, crossing her arms, she sighed. "I didn't think you'd watch the human news—"
"Human? This is everywhere, Shepard. The entire galaxy is going to be watching this trial, and from the looks if it, they want blood." His voice softened, his tone gentle. "You're in trouble. Let us help you."
For a second he thought she would consider it. Then, "No. None of you can come to Earth with me—we've been over this. Even you. Humans don't like turians, remember? You wouldn't exactly help my case."
He shook his head, mimicking her human gesture. "As if you'd win. Shepard, you blew up a mass relay. You killed over three hundred thousand batarians. You've been working with a terrorist group and known criminals. You caused an incredible amount of property damage every time you entered the Mako or Hammerhead—"
"Not helping, Garrus."
"Just trying to get my point across. The odds are against you. We need a back-up plan," He insisted. "Thane and I have it all worked out—when they take you to central booking, he'll—"
"Garrus, no." It was flat, defeated. Not a tone he thought he would ever hear from her. "If I'm convicted, I'm convicted. That's just another reason you all have to stay away; you'll have to fight the Reapers when they come."
In a flash he closed the distance between them, his face inches from hers. "Shepard, have you lost your mind? You can't just give in and put honor over reason!" The last few words practically hissed out, and she matched his steely glare.
"Well, I'd make a pretty good turian, wouldn't I?"
He wanted to hit her. He wanted to shake her, scream, make her understand. She could be just as stubborn as him; Sidonis was a testament to that. Standing in front of his scope like that made no sense at the time, but in the long run he could see what she was trying to do. But this? He settled for letting out a snarl, leaning in even closer so she could feel his breath on her face. It was an odd struggle for dominance, and he had to prove himself the stronger.
"If I get convicted, I'll break out on my own. It's my own damn fault. None of you should risk anything for me."
"And why not?" Her anger was only fueling his, and he placed a hand on her shoulder, aware that his talons were sinking into her skin. If she had flinched, shown any sight of pain, he would have pulled away and apologized. But that infuriating stare only made him dig deeper. "Tell me why, Shepard."
"Because I care about you, and I can't lose you. Any of you."
At that he released her, exhaling and closing his eyes. Even though he had been expecting that response, it still hit him hard.
"And we care about you. Shepard, you're our commander. Our friend. We're not going to let you go through this alone."
When he opened his eyes again, a soft smile had emerged at the corner of her lips, words forming. "That was cheesy, wasn't it?"
He paused, waiting for a translation. Once he got it, he laughed, mandibles flaring. "I would be lying if I said no. But I understand. Come on Shepard, remember Sidonis? I asked for your help because I knew nothing could stand in your way. You're the best at what you do, and so are we. Trust us, like we trust you."
"I…you're right. Of course you're right." She lowered her head, putting her hand to her brow. When she looked up again, her eyes were bright and her smile had widened. The Shepard that had been wallowing in sorrow for the last few days was gone, replaced by the one he would follow anywhere.
"Tell Thane that plan will work if I can't smooth-talk my way out of this," She continued, eyes dancing. "And no, I don't want to know what it is. Surprise me."
Her happiness was contagious, and he found his spirits lifted as well. It was only when he glanced at her shoulder that he grew somber. Observant as ever, she shook her head.
"I was sitting in here, drinking and bitching. You cared enough to come down here and knock some sense into me. Don't you dare worry about a couple of cuts." Instead of tending to her wounds, she reached over and grasped his shoulder, squeezing tightly. "I owe you one."
"You owe me nothing." With that, he grasped her uninjured shoulder and mimicked her gesture, sending her a brief nod before turning to leave. "I'll say hi to the family for you. My father can't wait to meet you."
Her laughter followed him to the elevator.