If you had to pick one episode/story that defined your character, which would it be?
This was a hard one to narrow down, because there are so many moments that have defined who Jack is. Obviously, the immortality is a big one, and the easiest choice. But at this point, I really don't think that's the biggest factor. It's important, yes, but I think how Jack has dealt with it and the things he has gone through because of it are much more meaningful than the act itself. And even once that's narrowed down, you basically have all of the Torchwood series; because he is the main character, the episodes always seem to revolve around him in some aspect, whether focusing on him as a character or his role in regards to the rest of the team.
But if I had to pick one single episode to define Jack, my choice would have to be Small Worlds. For those of you on my f-list familiar with the show, I am aware that it's not exactly a fan favorite. (Nothing like fitting pedophilia, faeries, fisting, and death by roses all in the span of an hour) But it has a handful of key moments that really defined what sort of character Jack is in my mind.
The first would be, I think would be the opening shots of the episode, when we see him sleeping. It's not even the implied nightmare that I think is important, but rather his posture throughout this whole scene. He does not lie on his side or curl up. Instead he's stretched out flat on his back, hands folded behind his head, as open a posture as you can have. It shows not only his trust in the safety of the Hub, but also just how little disregard he has for his own safety, much more so than any gloating or running around during missions really shows.
Another key moment, I think, is when he hands over the child to the faeries. Here is this little girl,, no older than ten at most, being asked to be handed over to beings who's very whim could likely destroy the world as we know it, and have been clearly shown to have no remorse in taking human lives as they see fit. The only guarantee for her safety that stands is their claim of her as a chosen child. And with the weeping mother standing right there, and all of Torchwood watching him, he hands her over.
Jack, for all his lack of discipline and disregard for authority that isn't his own, is an army man. He's used to making decisions which value the life of a group above the individual. Again, though, we are shown Jack's total disregard for himself. He doesn't care what his team thinks of him after this, whether they'll agree with his choice or not. All he knows is that he's made what he believes to be the right decision, and that's all the assurance he needs. He's willing to disregard his own social connections with the outside world and people around him if it means doing whats needed. He doesn't even argue with them over the fact; he lets them think what they will about it, confident in the knowledge that he is their leader and therefore still holds the last say. And this is a thinking that's only encouraged by the rest of the team; as always, they all fall back in line soon enough, ready to follow orders and do as their leader instructs.