Sylvia's team, at least, was disciplined. Unlike the witches in the borough, they were not caught unprepared. They recognized the troll for what it was and acted accordingly.

A spell of binding: Sylvia drew a handful of salt from a small leather bag at her hip and threw it at the troll while the other witches began their chant. Caught by magic, the salt scattered through the air and landed in a perfect circle entrapping the troll, preventing it from stepping outside its bounds or escaping to the Other Realm. It was a crude barrier and would not last the night, but in the short-term it was effective.

A quick fix solution, because Sylvia knew there were other more powerful fae to deal with. The moment the spell was finished, they moved swiftly on.