John studies Ianto for a long moment, taking in his uncertainty, then tilts his head slowly.

"Well, I worked in a floating ancient city. My job was to keep it safe and lead a reconnaissance team on missions. A team, because I'm pretty sure nobody who has ever met me would put me in charge of meeting new people alone. See, the point of a team is that everyone is good at different things. So you're here because you're good at things I'm not good at, and since we're here together to research dragons and bandits I think you have exactly the right skill set. I just had to get you here alive."

So really, if there's nobody to fight John is pretty sure his skill set is quickly going to go to waste here -- no matter what Ianto might believe. He's probably better suited to solving this puzzle.