I feel that it shoukd be mentioned that by destorying the brigde before Jim could get out with Enrique, they inadvertently escalate events to the point that led to his escape in the first place, right?
Well, yes and no. It was actually Usurna's fault since she's been sided with Gunmar the whole time. i mean, to me, it was like she used the trolls' skepticism of their first human Trollhunter to get rid of him. Maybe even distracting them from realizing that Gunmar has already infiltrated Trollmarket, thanks to wasting their precious time blaming Jim for releasing Gunmar and following Usurna's leads. They never stopped to realize that Jim was in a cage the entire time, and Usurna "framed" him for murdering Vendel, and most of them actually believed her.
So, mostly yes. The Tribunal meant well, but they make the most terrible decisions regarding Gunmar, due to their big fear of him. I mean, one of the leaders briefly stood against Gunmar, but she was a complete coward for not fighting against him. Gatto even disappeared at his mere presence. Vendel was by far the only sane member of the council because [juding by how he recorded Usurna's evil doings], it was implied that he was suspicious of her loyalties and placed his beliefs and trusts into Team Trollhunters, knowing they will stop Usurna and Gunmar, one way or another, even without the Tribunal.
I'm honestly kinda glad the Tribunal was disbanded after Gunmar's takeover. It would really come to show that they would start a new Tribunal, one who will be prepared for any changes and accept them instead of wasting time.