Problem #1-- coffee breakers wandering all about the vault

Problem #2-- Bedrooms can cause unwanted breeding, and storage rooms make people without high endurance unhappy.

Solution-- Break rooms! These would have no stats attached to them so anyone can hang out in them without happiness penalty and with no risk of breeding.

Break rooms would be very handy for keeping your coffee breakers in a handy spot where they're out of the way and easily found while waiting for assignment. This would be especially useful when shuffling people around between training rooms, such as when someone who has maxed out a skill is taking up needed space but has nowhere else to go, or when the wasteland explorer limit has been reached.

Or... remove the explorer cap, extra dweller problem solved!

Break room will consume power.

It it easy to find out dwellers in break by sorting. I dragged them to storage rooms on guard. No problem.

The point is limit of dwellers in the wasteland and how frequent incidents occur.