Rider could tell from the way Rin was acting that she was profoundly uncomfortable with what her sister was doing. Not that she could blame her, of course, since she too was not happy about it, but nevertheless she was worried that Rin might reject her sister or try to escape. Sakura seemed to pick up on Rin's disapproval too, becoming noticably less happy. Rider's heart almost broke as she heard her clearly-distraught master ask her elder sister if she thought she was bad.
Still, if Sakura had realised that her behaviour was unacceptable, she might stop doing it, which was a good thing. But, it depended on Rin not screwing things up by pushing her sister away, as she had done in the Grail War all those years ago.
Please be nice, Rin..., she thought, hoping that this version of Sakura's sister had lost enough of her hard magus exterior over the years since her Grail War that she would respond to her sister's pleading with warmth rather than the sort of cold, unfeeling rebuttal that she'd given back in the cavern at the climax of the Grail War.
Rider breathed a sigh of relief as Rin did as she had wanted, pulling Sakura into a soft hug, gently stroking her hair and reassuring her that she had never thought of her sister as a bad person, even if she might be misguided sometimes. She smiled as she watched Rin comfort her now-sobbing sister, reassuing her of her basic good nature, whilst not condoning her actions in this situation.
Sakura continued sobbing in Rin's arms, telling her how lonely she was, and how much she'd missed her sister and lover. Then, Shirou spoke up, saying that they needed to get back home, to which Rin agreed, noticing how Sakura was practically falling asleep in her arms. She was also clearly keen to leave herself, judging by the way she was shivering, and Sakura picked up on her need for clothing more suited to the weather.
Before she could start discussing how they would get back home, however, the other Shirou spoke up, asking if he was free to leave and glaring at the two sisters as he did. Rider glared back at him, as best as she could through her blindfold, angry that he might have worstened Sakura's already-fragile mental state. And, indeed, she was right. Sakura, hurt and upset by the tone of his voice, ran towards the other Shirou and hugged him, tearfully begging him for forgiveness. Rider glared at him once more as he stood there, clearly unsure how to react, before he put his hands around her and returned her hug, causing Rider's glare to change into a smile. At that, Sakura relaxed, mumbling before falling asleep in his arms, happy that he had forgiven her.
Rider was not so sure, though. He'd shown compassion to her, certainly, but that was what she'd have expected from Shirou. Whether he had truly forgiven her for what she had done was another matter entirely, as was whether he would be willing to see her again, as Sakura would undoubtedly wish.
Rin, meanwhile, smiled at the sight, before turning to Rider and speaking.
"You might wanna get her home", she said, before turning to address the other Shirou, saying she wanted to talk to him.
Rider frowned. Rin's words made it sound like she wasn't intending to come with them, and she knew that Sakura would be extremely upset if she lost touch with Rin so soon after finding her. Leaving Rin here with no way to contact her was simply not an option.
Before she could say anything, though, Sakura's Shirou spoke, agreeing with Rin, before the other Shirou scooped Sakura up into his arms and carried her over to Rider.
“You should take her,” he said. “Will my leaving now be a problem?”
Unfortunately for him, though, Sakura did not seem to wish to let go, wrapping her arms and legs around him.
"Yes, I think so, if you can get Sakura out of that hug at least. She seems to have accepted that this was not a good idea.
But, please, don't hold this against her, or her sister. I know what she did wasn't right, but she didn't mean you any harm, she just wanted you to be safe. And Rin wasn't even here when I left, she had no input into what happened.
And, please try to keep in contact with Sakura, she truly cares for you and will want to know you're safe, and to be able to see you again. If you could give us some more information so we can find your house more easily, it would be very helpful in reassuring her", she said.
Then, she turned to Rin.
"Yes, I do need to get her back home, but Sakura will be very upset if she wakes up and you are not there, particularly since she has no way of contacting you. If you need to talk to Shirou then that is fine, but please come back with us afterwards. You're cold and you quite obviously have nowhere else to go, and Sakura needs you to be there for her. She's not seen her sister for three years, if you leave now she will be heart-broken", she said.
Then, she turned back to the other Shirou, and gently put her arms around Sakura.
"Sakura, please let go of Shirou, we need to get you home", she whispered softly.