Later
Leo and Lydia were looking for Scott and Stiles as the police were leaving. Also, the buzzing noise was starting to get louder and louder. Eventually, they found them. "The police are leaving. Why are they leaving?" Lydia asked. "The police?" Scott asked. Leo nodded. "They must have cleared the building and grounds, which means he's not here." Stiles said. "Who? What are you guys--" Scott said but was cut off. "He has to be here. That sound... that buzzing we've been hearing? It's getting louder." Lydia said. "How loud?" Stiles asked. "It's loud enough to make shouting sound like whispers." Leo said. Then, Leo, Lydia and Stiles went to find the sheriff.
Lydia and Leo stood off to the side as Stiles went to his dad. "Dad. Dad!" Stiles exclaimed. "Yeah?" The sheriff asked. "You can't leave yet." Stiles said. "We got an eyewitness that puts Barrow by the train station..." the sheriff said. "Let's go, Stilinski!" Rafael said. "Whoa, whoa, Dad! Please, just-- Lydia and Leo said that he's still here." Stiles said. The sheriff looked at her to see them talking. "Did they see him?" The sheriff asked. "Not exactly, no... Well, not at all, actually. But they has a feeling-- a supernatural feeling." Stiles said. "...Lydia and Leo weren't on the chessboard." The sheriff said. Stiles shrugged. "They are now." Stiles said.
"Kanimas?" The sheriff asked. "Um, Banshee and Siren." Stiles said. The sheriff groaned. "Oh, God..." the sheriff said. He looked over at them. "Who's what?" The sheriff asked. "Lydia is the banshee and Leo is the siren." Stiles said. The sheriff sighed. "I know, I know how it sounds. But basically, it means that she can sense when someone's close to death. And Leo can also do that through a psychic link they share." Stiles said. "Can they sense that I'm about to kill you?" The sheriff asked. Stiles looked at the two and they waved at them. "I don't know..." Stiles said.
"All right, look-- I'm not saying I don't believe, but right now, I'm going with "eyewitness" over "Banshee and Siren." We're leaving a few deputies here. The school's on lockdown until three o'clock. Nobody comes in, nobody comes out." The sheriff said. Stiles looked shocked by this. "Buddy, that's the best I've got right now. That's the best I can give you, Stiles--" The sheriff said but Stiles cut him off. "You're leaving me here??? That's not-- that's the worst." Stiles said. 
Later
The school was in lockdown and Leo, Lydia, Stiles and Allison were in a classroom. Allison was sneaking out through the window. "The bestiary is literally a thousand pages long. If I'm going to find anything about flies coming out of people's bodies, it could take me all night." Allison said. "And remember-- the word in archaic Latin for "fly" is musca." Leo said. "Got it." Allison said before jumping out the window. Lydia and Leo turned to Stiles. "Where do we start?" Lydia asked. "Upstairs." Stiles said. Stiles looked at the clock and saw it was 2:30. "We gotta go." Stiles said. 
Lydia, Leo and Stiles look through the art room. "Scott and Isaac are in the basement, right?" Lydia asked. "Yeah, with Ethan and Aiden. The plan is they meet in the middle in the boiler room." Stiles said. "All of the wolves-- all of the ones with glowing eyes are in the basement at the boiler room?" Leo asked, hoping Stiles would catch on to what he was saying. Luckily, Stiles did. "...Oh, my God! An engineer could use a boiler room to blow up the whole school. We have to get them out of there." Stiles said. Leo nodded. "We have to get everyone out." Stiles said. He then pulls the fire alarm. 
Stiles looks pretty pleased with himself until Lydia and Leo looked at him, distressed. Coach is standing right next to him, glaring. Coach then started hauling Stiles out of the building. "Wow. Pulling a fire alarm on Mischief Night is one thing-- doing it when there's a mass murderer spotted nearby is insane! If I was four years younger, I'd punch you!" Coach said. Stiles looked at him confused. "What? Coach, that doesn't make any sense..." Stiles said. "Oh, well it does to me!" Coach said. Coach walked back into the building.