He assumed that he'd unintentionally hit on some author's phrase that she recognised, and later he'd ask her to tell him where it was from, however much of it she remembered.
When she asked him to help her with the bath, he said, "Of course, yeah, that's a good idea. C'mon..." He got up with her and moved over to Gemma's old-fashioned claw-footed tub, opening the faucets to run the water. He'd seen her nearly naked before, back when they hadn't known each other well enough for him to look, and they'd have their chance at intimacy again. They'd chase away the terror of all this by the fact of their own closeness.