His heartbeat is a constant rush in his own head, only broken up by the sounds she makes, the ones that make him want to lean in to hear them as close as he can so he's the first one there the second they tumble from her lips. She's in his head by the way his body is starting to respond to her - stirring in ways he'd long been convinced he wasn't able to experience without serious risk.

There's nothing to bring him back to a reality - no heart monitor on his wrist, and the only dizzying sensation he has isn't at all like the feeling he gets before he slips into blackness, before the Hulk takes over. It's just the headiness of her warmth, her scent, her hand trailing against his skin, and he's fumbling behind her for purchase before guiding her up against a shelf, pressing her there needfully yet gently.