Seth does remember symbiosis, and it's with that in mind that a shallow laugh bursts from his mouth before he shakes his head and latches onto Anna's wrist like a good parasite should. He cups the back of her wrist with his injured hand and sucks eagerly. He knows what blood tastes like, more or less, but Anna's blood is different. It's a difference that makes it slide down sweetly as he closes his eyes, blood trickling from the corners of his mouth as he swallows gouts of it. It's an appetite that might remind Anna of herself, just a few moments ago, and it's only when he feels it stirring in himself that he pulls away with her blood smeared messily across the lower half of his face and sucks in air, pupils dilating almost impossibly fast.
It doesn't hurt, although it should. Healing aches even when it's slow, so sped up like this it should burn, but Seth tears off his towel with desperate fingers to watch his palm seal shut, the mark vanishing instantly under blood, and then he sags in his wheelchair as the rest of it goes to work, his eyes closed as he pants shallowly. He never lets his hair get mussed, never mind act this undone, but here he is, and it's wonderful.
His arm goes first, bone knitting together in the straightened position the doctors left it in, as residual bruising hidden under his clothes vanishes into perfect pale skin. Then his leg, his body driving out two metal pins so hard that they crack his cast, and then finally he feels the phantom of his severed finger twitch, jerk, and surge back into prickling awareness. He shudders where he sits, and then he goes still, breathing hard.
When he opens his eyes the room is impossibly bright, and he can feel his heart tripping fast over itself as he sits upright, smiling with incredible satisfaction. He leans down without pain to scrabble at his leg cast, slamming it against the floor, which widens the crack but doesn't quite split it.
"Can you--help me get these off?" He asks, raising his head, his words rushing and bunched together, flooded with eagerness and energy.