With my low moonlevel I can only give you the gist of it
Hillshire receives a hit order, but goes by himself because he's feeling protective about Triela. She had seen the news coverage of the killings and after seeing the wound on him she puts two and two together, throws a small fit about why he didn't take her with him, since that's her job. Hillshire snaps something at her, and she runs off crying.
Delicious crying long-hair Triela.