Much like the other knights, Terrence isn't exactly a fan of being tied up against his will. Tied up consensually, sure, but not like this! That said, he's evidently a fair bit more okay with it than some of his fellows seem to be. That, combined with the fact that he has one of the less useful powers for helping them immediately escape, leads to the pragmatic decision to simply stay quiet for the moment.

Garrot(s) is/are on the move, so he'll be freed eventually. For now it's more reasonable to just let him/them help out the ones who are panicking or have abilities with more short-term impact first.