Sarah's head snapped up at the cough, her focus on their hands so great, willing his hand to move again, that the sound actually startled her. What she saw happening was almost too much to process at once, Sarah blinking rapidly to try and clear her vision while making the polar shift from knowing he was dead to seeing him alive, breathing and healing right before her eyes. The healing wasn't hard to miss with his charred shirt laying it bare for scrutiny.
And then he whispered her name and it was, in the fevered height of emotion, something she did not hesitate to label as the single most beautiful sound she was certain she'd ever heard, because it was from him, alive. Her arm was there before he'd had a chance to get completely upright, there not just to help him but to pull him to her. The clinging was awkward with their hands still joined but fierce just the same, because it wasn't one-sided. She was holding Peter who no longer felt like a ragdoll in her arms.
He was alive. He had been dead, even now she knew she hadn't imagined his lack of heartbeat or breath, not with how hard she had looked and felt for it, but now he was alive. If she repeated the word in her head enough, it might help stabilize her, as she was still reeling. The tears had turned to relief, though grief and fear was still there, a swirling mess of emotions from the last ten minutes of this entire confrontation, none receding so much as making room for others.
"Peter, you were- I saw- there was-" No thought could be completed through her sobbing before the next one began, leaving her babbling in broken fragments as she clung to him.