'The only thing I really worry about (and I can't believe that I'm actually *concerned*) is that Ianto will fall quite deeply into the relationship where Jack will only let himself ever sit on the surface, bringing much heartbreak for the teaboy in later episodes.' I worry about that too, Ianto seems like the kind of person who, when he falls he falls hard(See:Cyberwomen-Lisa), whereas Jack probably does 'sit on the surface' because he knows that he will out-live Ianto.