Unwelcome face
All of the Blade's knew what Sil had said to Hilston before he had decided to finish him off in the way he had done. The video that had been recorded was watched by them all multiple times, not just by them but nearly everyone in the Shelter.
The drones had advanced technology that was able to pick up clear audio in a specific direction despite neither one of them not having microphones on their bodies. During the fight, Sil didn't exactly whisper the words to Hilston in his fit of anger either.
It was then that Sil had claimed that he didn't care about the reason Hilston had done everything, that no matter what, it wouldn't make up for the crimes he had committed, but after the fight, something had changed. It had to have for Sil to suddenly ask this question to his brother and sister.
This was due to the people around him, and not just any people, but those in the Cursed faction.