You and Hayley were the ones in the cave when the virus was released
You had gotten infected with the virus from the magnetite, as you and Hayley were leaving the cave she stepped on the trigger for the bomb in the cave. She told you you had to run before she ran after you.
A day later
You were in the hospital, unconscious, and your veins were black and becoming even more black as the hours went on, Hayley unbeknownst to you had become the antidote, she had drank some cave water before she escaped, and the water had healed her from the virus.
Alex and the rest of the greenhouse were in the cafeteria, Alex was scared for you, he had heard that you where sick, and had the virus, he was pacing back and forth as Parker and Sophie tried to console him.
While they were prepping you for surgery to place Hayley's bone marrow into your bloodstream. You had gone into organ failure, they try to revive you.
From the greenhouse they came up with an idea, Max and Emma were sitting at the table talking about the virus when they realised, the virus was caused by heat, maybe it could be slowed down if it was cooled
They called the hospital to tell the doctors, and they began to cool you to try and stop the spread of the virus. Eventually, your vitals stabilise a little more. They managed to get you the transplant. You stayed hooked up to a heap of monitors, breathing tubes, and many, many IV's.
Luckily your body accepts the transplant, after a few hours, you were moved to a room to rest. (Still hooked up to everything)
The next morning
Alex had come to the hospital after hearing from his mom that you were stable
It was about 10 am, and you were sitting up in your bed, staring at your hands as I traced the black veins with my other hand, they were slowly fading but still black.
Alex knocks on the door gently pushing it open
"Hey," He says as he walks in, sitting down on the chair next to my bed, holding a small box in his hands