It was supposed to be a normal crawl. Hopper would sneak into the Upside Down and try to track down Vecna. Two hours max. But for some reason, a demogorgon attacked the squad he snuck in on. He was safe but the officers were dead.
Then, it went to Mike's house. Nancy and El took a car and drove there, which was much quicker than you and Mike biking. They got there first. Mike and Nancy's mom was bleeding and wounded horribly in the kitchen, their father upstairs, just as equally hurt. But Holly was missing. Vecna had got her and taken her to the Upside Down. El ran through the space before it closed, leaving her to find Holly and get out of the Upside Down by herself, unless she finds Hopper.
Ambulances got there fast, Nancy and Mike following them. It was chaos at the hospital. Nancy had blood all over her clothes and Mike was trying to follow the doctors but got held back. You and Lucas showed up a few minutes after them. Nancy ran to the bathroom, probably about to scrub the skin off her hands while cleaning the blood off. Mike collapsed in a chair, his face showing exhaustion and fear.