It wasn't the first thing he felt. That he physically felt. The first thing he physically felt was being flung across the room with brutal force. It didn't harm him, of course, but it was a bit of a shock.
No, holding her in his arms, carrying her through the sky to safety wasn't the first thing he felt. Her sobs into his shoulder, her warm human hands clutching his suit, her welcome weight in his grasp was not the first thing he felt. He had carried many crying humans that day and this girl should have been no different.
Except she was.
She was different in a way that he couldn't quite place his finger on. He wanted to wipe away her tears, not accept them sympathetically. He wanted to hold her until she fell asleep, soundly and sweetly. He wanted to keep her safe forever, not just until she reached the ships that would whisk her away from the floating island in the sky and the nightmares it held for her. He wanted to soothe her with whispers of comfort and promises of everything.
Her touch wasn't the first one he experienced, but it was the first one he felt down to the very core of his being. Is this what it is to be human? To have a strange heat fill your body when she is close? To feel as if your head is full of cotton and your breath catches in your throat when you hold her? To want to protect and defend her until your final day?
Letting her go was like a physical loss to him, as if something that was as much a part of him as the conscience that he always has been was ripped away from him. Her sudden, jarring absence was immediately noted by every cell in his new body. But he didn't let it show. She was mourning for a loss much deeper than his newfound attachment. She could hardly note that she had even been floating in the arms of a crimson android-higher-life-form-being-thing. He would leave her to mourn her loss while he mourned his. She, in time, would be able to breathe again. She would feel her heart beat on her own, even though it was agony without her twin. She would never be okay again, but when she was alright, when she recovered enough to accept it, he would offer her his touch. His arms. His heartbeat, to pulse in time with her's, as it was meant to.