Normal classes are cancelled for a Safety Patrol video about trolls, which teaches total and utter nonsense that Frida and David's personal experience with a Troll completely contradicts. Frida, disgusted that algebra was cancelled for a Propaganda Piece, stops and ejects the video, debunks its content by, among other things, asking the class if they've personally seen a Troll eat a human being, and stages a walkout, which the entire class joins.
Frida: You shouldn't have to sit here and be taught lies, and I won't.
Despite reprimanding Frida for disrupting class, Ms. Hallgrim is shown to actually be proud of her students for standing up for their principles, and later voices support for their protests.
When Johanna is cornered by Trolls, Alfur flies his pigeon Cedric into one of the trolls' faces as a distraction, allowing her to escape. It becomes a Heroic Sacrifice when Cedric gets eaten by the troll (though fortunately, the end of the film reveals that Cedric survived).
Hilda, seeing Johanna threatened by the Bearded Troll, immediately acts to protect her mother. She leaps almost to his eye levelnote keep in mind, the Bearded Troll is barely smaller than Trundle, punches this behemoth in the face, and grabs onto his nose, causing him to lose his balance, trip on Johanna's car, and stumble into a nearby ravine as he tries to get her off. As a testament to Troll physiology, both of them survive, and Hilda immediately climbs out of the ravine.
After Hilda and Baba finally reunite with their mothers, Erik Ahlberg escalates the situation by taking Baba hostage and threatening the Trolls (including Hilda) with his ray gun. Johanna promptly declares that she will disarm him if he doesn't stand down. And she does.
During this time, Baba reverts to Troll form because the spell has been nullified, and bites Erik's arm to get him to stop threatening Trylla and let her go.
The Bearded Troll stopping one of Trundle's boulders from killing David, who is in the targeted bell tower at the time after helping Frida escape Trundle's followers.
Erik outright ignores Hilda's warning that Trundle is trying to provoke the Safety Patrol into attacking to cause the city's destruction... but Gerda listens, and outright refuses to follow his order to fire on Trundle. Unfortunately, it results in her being relieved of duty, but this doesn't change the fact she actually recognized the danger.
Unable to convince the Safety Patrol to stand down, and with Amma stirring out of rage at Trundle's death, Hilda decides to subject Erik to the vision she saw. She runs to Trundle's eye, tells Trylla to throw her, and slam-dunks the eyeball right on Erik's head. The moment the vision ends, Erik, comprehending what he's about to cause, orders a ceasefire, calming Amma and saving Trolberg.
While Erik is never shown publicly acknowledging his mistake, and in fact accepts a medal for his role in ending the crisis, he does seem to privately accept that it was his fault the Mountain King crisis got as bad as it did. Upon receiving the medal, he immediately announces his retirement and hands the reins over to Gerda, knowing she will be a far better head of the Safety Patrol than he was.
