His first instinct is to say no one because none of these bear remembering, but he glances down, frowns. The sadness in Jim's voice is palpable and maybe... he wants to see it. Maybe he wanted to all along, because it meant somebody cared.

'Training,' he replies, simply. His voice lacks the bitterness it usually does when he refers to his experiences, which indicates this is a choice, and he's learning from someone who means well. He's not merely putting up with being hurt or letting himself be hit for the sake of feeling pain. He derives no joy from that.