The AU had the kids split into pairs with color-coded ties. They all had chips implanted in their hands that allowed them to open certain doors that would give them supplies to survive.
I think if I remember correctly they broke down like this
Blue = Water
Purple = Clean clothes
Yellow = Safe room
Red = Medical supplies
Green = Food
The catch was that you need both people to open the door and the lock worked in such a way that you could potentially trap one of the pair there indefinitely. One person had to put their hand on a reader which opened another panel. The second person had to stick their hand inside and rotate a switch to open the actual door. It was especially dangerous for the Yellow team, since if they wanted the safe house door close both members of yellow would have to be locked outside, but if they wanted to close the door they could leave one yellow team member stuck outside with their hand in the lock.