Zombie Dream, in bits and pieces

Unfortunately, I can't remember most of this dream, so this is mostly going to be a bullet point summary

We started in the lobby of a 12 story hotel. We barricaded the doors and divided into groups of three, One on the 10th, one on the 11th, one on the 12th floor. I was on the 11th.

We blocked the doorways and essentially got rid of all contact with the other floors. We tried to live as normally as we can, though floor 11 took over roof and fire escape access so we can observe our surroundings.

At one point, a group of us tried to go up to floor 12 and it was in total chaos, we almost got shot and it appeared to have reverted to some sort of tribal state, where the 12th floor broke up into a few groups and they fought each other for food. We couldn't do anything to help with just the five of us, so we left and blocked them in again.

We went up to the roof to observe the surroundings. There were a lot of zombies milling about but they didn't seem interested at all. One of the guys I was with got pissed off and shot into the distance. We tackled him, and watched to see if the zombies could locate us, but luckily most of them actually headed in the direction the shot was fired, and very few stayed around us.

At one point I ended up alone on the third floor fire escape to get a closer look at things, and then went to patrol the floors. I found about two zombies on the lower floors, probably there from before we got there and were just missed. When I got up to the 7th floor, it looked like someone had completely ripped out the 8th floor, making the 7th two stories. At the end there was this giant contraption. Apparently the 10th floor had expanded downwards and were making sacrifices. Two women walked passed discussing the next day's sacrifice which apparently went that two people would fight each other to get out of the giant contraption, and once the first person was out then they would lock the other person on where they would get sprayed with some sort of drug and starve to death.

Unfortunately, of course, that means I was discovered and had to participate in this sacrifice, except now there were three people instead of two. When one person got out, I was about to reach the door but they closed it and gassed both of us. I know that some small boy helped me get out, and his father, him and I made it to the stairwell where we went back up to the 11th floor to report.