"I'm not leaving you here." She doesn't have much choice but to stop, though she does give another insistent push before giving up. "We're in this together."

It's the closest she can come to saying everything that's hard to put into words. He's the only thing that connects her back to home besides memories. He's family, without quite being it--someplace far more important than a mere friend. He's part of her group, and she's not going to leave him behind.