When the detective finished taking her incident report, Kate glanced up and saw Castle still sitting in the back of the ambulance, no doubt having asked the paramedic to rewrap his hand at least once because it was too tight. She knew she shouldn't, but she made her way to him, all the while justifying herself by thinking that she was just going over there to say thank you to a friend, but she knew that was a lie.
As she clambered up into the ambulance to sit across from him, the image of Josh closing the door behind him as he left for Africa floated into Kate's mind, unwelcome and judgmental
"Hey there Chuck Norris." She said, catching Castle's eye and pushing all thought of Josh away. He laughed and began unraveling his hand wrap again. "How's the hand?" She asked as she gingerly took the wrap in hers and began loosening it. She tried not to, but her finger grazed the back of his hand and she felt fire speed up from it as her heart began to pound a little faster.
"Ah, excruciating." He wasn't looking at her, they were both concentrating on her fingers as they rewound the wrap around his knuckles. There was nothing for it now, she had to touch him, there was no way of wrapping his hand without doing so. And with every graze came a newfound heat and Kate couldn't decide if she wanted to pull him to her again, or shove him away for adding yet another layer of complication to her life. She glanced up into his eyes fro the briefest of seconds as they discussed how Ryan and Espo were doing, and her choice was made.
Kate wanted his hand on her cheek again, and his lips on her mouth. She wanted to taste him again, to feel his chest against hers, his hair under her fingers. She wanted to fully immerse herself in his kiss; she felt slighted by the fact that earlier she'd had to break it and walk away. She wanted his hands everywhere, his skin against hers. When she thought about how he'd said "that was amazing" she almost broke down, but no, she couldn't; their relationship was fat too complicated, not to mention the fact that she was with Josh.
So, instead of acting on the feelings welling up inside her, she said simply: "Thank you, for having my back in here." In those eight words, Kate tried to convey the full magnitude of her gratitude for what he'd done for her. He had literally saved her life by tackling Lockwood, but it went further than that. She'd seen his expression as he straddled the unconscious Lockwood, it had been identical to the one she'd felt on her own face when she shot Dick Coonan, and the one on Alfred Candela's face when he offered to make the money drop to his daughter's kidnappers. It was primal, the face of someone willing to go to any length to protect another person, the one that said whatever needed to be done, would be.
As Castle looked at her and said "always" she saw the exact opposite of that primal expression; there was, dare she think it, love written in his gaze. Kate averted her eyes because if she hadn't she was sure she would have jumped him. She sat there for a moment in silence, allowing herself the luxury of imagining a few of the things she would like to do with him. But soon enough Ryan and Espo walked up and the moment was lost, leaving her feeling guiltier than ever as she thought how unsatisfied she was.