Event Idea - Vault 11
So this would be directly based on the social experiment of Vault 11 in fallout new vegas, where the people in the vault had to sacrifice one of the members every year or they were told they'd all die.
Here this could work as a gamemode without antags, and depending on the number of players, it could be something like "5 people have to be sacrificed every 20 minutes or CC will kill everyone".
The sacrificing method could vary but it happening in the AI core with the lethal turrets would fit perfectly as to how it happened in fallout new vegas.
Of course, the ending of the story in fallout is that the correct choice was to not sacrifice anyone, which was learnt when nearly everyone died in a civil war inside the vault, perhaps the event could play into it or perhaps the threat of everyone dying if no sacrifice is made is truly real 