[ He falls silent, his eyebrows knitting together once more. He lets his gaze drift away, across the ice, somewhere toward the bare skyline. No, it isn’t Claire’s story to tell, but it’s a heavy tale, and Theon dislikes recounting it again and again. It only takes him back to the moment it happened, forces him back into a dark place in his mind, and sometimes he fears he may never escape it.

He’s silent for so long, it may seem as though he isn’t listening to her at all, or as though he’s disconnected entirely from the conversation, but eventually he does respond in quiet voice. ]

A garrison is…it’s the men who make up the armies.

[ He scrubs at his face with a gloved hand, trying to force himself back to some semblance of Theon. ]

You can ask what you like. You're likely to get three other explanations from the other Westerosi, so you may as well start now.