Shinji would have been more than content to let the conversation fade into that comfortable quiet the two of them had become so good at, letting the warm water ease the tension out of his muscles while Kai's hand tangled up in his eases the worries out of his mind, but then those words meet his ears.

Ah...? Ah. He gets, at least, the basic sentiment that would drive a wish like that, even if he's unaware of the particulars of why it could be relevant.

"I won't," he assures him, voice just as soft and quiet. "I don't think I could, but I definitely never want to."