The previous day...

"You sure this is alright? I mean, we're tampering with some pretty high grade equipment." inquired Gibson as she made her way into the hull of the Thunderbolt. Fumbling around, she found her hands clutching one of the heavy shells of the tank.

"I mean, if anyone should be doing this, shouldn't it be you, Simpson? After all, you're the one with all the technical knowledge." asked Gibson, annoyed that she was dragged into the mess. The hatch on the Thunderbolt's turret opened, as Simpson's surprisingly pale face emerged.

"Me, handling the bloody breech of the Thunderbolt? Yeah nah. I don't wanna end up like Yarra with her arm being sheared off. You're a loader anyways. It should be fine."

Gibson carefully maneuvered her hands away from the shell she was holding and towards the breech of the 25 pounder gun on the Thunderbolt. Opening the breech, she carefully disabled any electronics, not wanting to repeat the unfortunate incident that happened with another student. Once she was sure nothing wrong could happen, she pulled the heavy shell from the breech with great precision before clutching it with her hands when it emerged.

"Ya know, we could have just gotten a shell from the ammo storage." Gibson shouted, her voice echoing throughout the tank. "Or we could have taken a shell from the ammo racks in the tank. But no, don't listen to Gibson, we have to take a shell out of a breech that has ALREADY TORN SOMEONE'S FUCKING ARM OFF!"

Gibson stood up, the shell fitting nicely in a cradle formed by her arms. Lifting one of her arms, she slowly climbed out of the tank, careful not to drop the high explosive shell on her way out. Standing tall on top of the tank, she looked down to Simpson, gesturing for her to get down. Suddenly, a loud voice echoed throughout the storage shed.

"Oi! What are you doing with the Thunderbolt?"

Gibson turned around, only to have her eyes meet two girls in school uniform walking towards them. She traced the voice to a tall girl with brown hair, and bloody red eyes, which terrified her, named Yarra. Next to her was a shorter girl with short blond hair, donning a large white ribbon that she identified as Murray. Yarra began to speak again.

"What the hell are you doing with that HE shell? Have you been tampering with the Thunderbolt's breech?" Yarra said as her eyes glanced over the 25 pound shell, as Gibson answered her question with a nod. Simpson walked around the tank to see what was going on, before Yarra sighed again.

"What were you planning to do with a high explosive shell? Please don't say what I think you're going to say," she said as Simpson stepped forward.

"Well, Australia Day is coming up in like a few days," Simpson explained as she was handed the eleven kilogram shell by Gibson, still standing on top of the tank. "And I was thinking of converting one of the HE shells into some fireworks."

Yarra and Murray looked to each other, before turning back to Gibson and Simpson with faces full of glee.

"That sounds awesome!" the two girls exclaimed, giggling with joy as they ran towards Simpson.

"It's good we have a pyrotechnician here with us," said Yarra, pointing to Murray. "Come on, let's go to my place. We should have everything we need."

Simpson gestured to Gibson to come with her, as she began walking with the two girls. Gibson, tired of everything, simply shook her head, as she left the tank store sheds, for her home, to go to bed.

It was almost 10pm, as Gibson got ready to take a shower. Today, she had come home extraordinarily late, and had spent far too long preparing dinner. As she gathered her clothes, she heard her phone ringing from her bedside table. Quickly grabbing it, she heard the familiar voice of Simpson, still as excited as she was back in the tank store sheds.

"Hey Gibson," she said excitedly. "Me and the girls are done with the shell. Come over to the tank sheds. This is not something you want to miss."

Gibson put down her phone, and contemplated for a while. In the end, she chose to sacrifice her sleep schedule and grabbed her coat, quickly exiting her apartment. Running down the empty streets, she quickly found herself in front of the store sheds, with three figures waving at her. Making her way towards the figures, she saw Simpson running at her, with Yarra and Murray next to the tank, holding what looks like a shell.

"This better be worth it, Simpson," she said angrily, "or I will be very, very upset."

"Oh, this is definitely worth it. Come on," Simpson replied. "Let's get in the tank and test it."

Gibson complied, albeit a bit worried that the girls hadn't tested the shell before calling her here. Climbing on top of the tank, she quickly entered through a hatch and sat in the gunner's position. Soon, the other girls followed, Simpson in the loader's position with the shell passed to her, Yarra in the commander's position and Murray operating the vehicle from the driver's position.

"Loading shell!" Simpson shouted, as she grabbed the shell and put it into the breech of the massive cannon, before reaching down and grabbing the propellant charge and placing it behind the shell, before closing the breech.

"Shell loaded!" she shouted, as Yarra's face filled with more excitement.

"Murray, drive the vehicle 20 metres forward." Yarra ordered, as she turned and opened the commander's hatch, before peeking her head out. Coming to a stop moments later, she took a deep breath before shouting her final order. "Gunner! Open fire!"

The tank shook itself as the eleven kilogram shell flew across the air, before detonating. The huge dust cloud that followed quickly obscured any pyrotechnic display, causing mass disappointment among the girls. Suddenly, Gibson spoke up in a very timid voice.

"Uh, Yarra, I think I loaded the wrong shell," pointing to the modified shell next to her, unused. The girls, now aware of what was going on, quickly got out of the tank, before watching the dust cloud settle. Once it settled down, they saw the true damage of their antics, as a huge hole covered the wall of the gymnasium they had fired at.

Yarra started speaking. "I think you might have loaded the wrong shell."