I don't own Wicked. This one's kind of long, so bear with me.
"Are you crazy?" Fiyero demanded with a ferocious glare. "Go back to Oz? After everything we've been through?"
"Fiyero, keep your voice down," Elphaba said softly, glancing up the hallway where Liir's room was located. "And I don't mean permanently. Just to help Glinda." When her husband's expression did not change, Elphaba locked gazes with him, willing him to understand what she was saying. "Fiyero, part of the reason I wanted to leave was to keep her safe! These rebels are trouble; if she hadn't had the Grimmerie that night..." She trailed off, clearly unwilling to consider what would have happened to her friend.
Fiyero sighed and some of the tension drained from his body. Gently taking his wife's hand, he pressed his lips against the back of it before looking at her with a gentle sorrow in his eyes. "Fae," he said quietly, using his nickname for her, "even if you do take care of the rebels, there will be other troubles down the road. You can't protect Glinda from everything. This sounds cold, but she'll have to learn to fend for herself. You and I did."
"No." Elphaba's eyes flashed with anger, and she pulled away from Fiyero. "I won't abandon her. I left Nessa and she died. That is a mistake I will not make again. I know I can't always be there, and I don't want to be. I'm not Glinda's bodyguard. But after everything she did for me, I'm not going to throw her to the wolves." Turning, Elphaba strode out the door.
Trembling, Glinda leaned against the wall. She had been on her way downstairs to get another blanket when Elphaba and Fiyero started arguing. What she had heard turned her blood to ice: Elphaba wanted to go back—go back to Oz!—and drive the rebels off.
Elphaba's unfailing loyalty had always been something Glinda admired, but now it was putting her in danger. I won't lose you again. Not after the first time. I can't live with that.
Something touched her arm. Glinda yelped and turned around only to find Liir crouched beside her. "So you heard it too, huh?" he asked quietly. "Mom and Dad can't go back; they've told me that story a hundred times. Only Mom said you died."
"W—what?" Even in her shock and fear Glinda felt insulted. "Why?"
"Dad said it was because they didn't want me to go looking for you and tell you the truth." Liir shrugged. "Makes sense, I guess. But anyways, if we're gonna leave, we have to do it fast."
"What are you talking about?"
His green eyes met her azure ones. "You're gonna go back to Oz and I'm coming with you. They don't know me. I know how to use a sword; Dad taught me. I can help fight. You know magic, right? With your spells and my blade, we can fight off those rebels."
Glinda gaped at him in utter horror. Had everyone gone mad? "Liir, I can't let you do that! Elphie would kill me! And what if something happened to you? I'd never forgive myself!" Liir opened his mouth to protest, but Glinda cut him off. "Absolutely not! When I go back to Oz, I'm going alone and I'm fighting my battles myself. None of you are coming!"
The sky was still dark with shafts of soft pink peeking through the trees as Glinda crept downstairs, eyes darting around like a cornered wolf. When the floorboards creaked softly under her weight, the blonde woman almost had a heart attack and jumped nearly two feet.
Two days had passed since hearing Elphaba declare her intentions to accompany Glinda back to Oz and Liir asking to go with her. She had shot Liir down and kept a wary eye on Elphaba, but to Glinda's surprise her old friend didn't approach the subject.
But that didn't mean she wasn't planning to do so, which was why Glinda decided on sneaking out like a bandit. If memory served her correctly, Elphaba was an extremely heavy sleeper and couldn't be dragged out of bed with anything less than a scream right into her eardrum. Liir was an uncertain player, as was Fiyero, but upon tiptoeing out of her room Glinda saw that both rooms had their doors closed, which hopefully meant the occupants were still asleep. With any luck she would be halfway back to Oz by the time her disappearance was discovered.
After going a few steps, Glinda turned and looked back at the house. Her heart ached as she realized that this was the last time she and Fiyero and Elphaba would see each other. At least they're alive, she comforted herself. At least Elphaba doesn't feel so guilty anymore and Fiyero knows that I forgive him. But try as she might, Glinda couldn't quite shake the feeling that she was abandoning them both just as they had done to her twelve years before.
As the blonde set off in her transport bubble, she was very unaware of a shadow creeping down below. Step by step, it followed her through the trees with the stealth of a panther, intending to pursue her all the way to Oz. Only then could its mission be fulfilled.