Rebecca wasn't sure why she walked so slowly back to heaven's portal despite the fact that her next courses of action screamed of importance: get back to the portal, free Sarah and Thomas, stop Castiel.
Stop Castiel.
The thought bounced around inside her head, begging for attention. Her mind drifted to the dark-haired soldier she'd known for thousands of years, and she came to the conclusion that the man she had just spoken with wasn't Castiel.
So, who are you, now? she wondered, thinking of his recent threat to her: "I don't relish hurting angels, but I've come to the conclusion that I excel at it."
Castiel, she thought, what has happened to you? When did we become the enemy? And thinking it hurt. More than she'd even allowed herself to acknowledge before; While the other angels spoke of Castiel in derision, somewhere, secretly, a part of her pretended it wasn't true.
It's not that she knew him well. True, she'd spent thousands of years with the angel, but heaven wasn't a place for human-like relating with one another. Especially between soldiers like Castiel and herself. But, in a secret, deep part of her, she'd noted that there had always been a spark about the angel she'd admired. He was different, even if she couldn't figure out how. And, until now, she'd never had to explore that tiny realization. But, when Rebekah had looked at the angel as he'd spoken, she'd seen something that only caused her further confusion. In Castiel's eyes, she'd seen regret.
If you really don't want to hurt us, she thought, then why do you keep doing it? But, she already knew the answer. All of heaven did. He'd chosen Dean. And tonight, Rebekah had brandished a knife against her comrades neck and told him he was no longer welcome in heaven.
He betrayed us, she thought, it should be simple. But somehow, it wasn't. Nothing had been for the angels. Not in a long time. And so she walked slowly to rescue Sam's captives, letting her mind explore a foreign feeling creeping up into her chest. A feeling of uncertainty.