Is it possible to put a dweller on coffee break?
No, not really. Coffee Break is the status for an unassigned settler, from my knowledge this only happens in the following ways:
- Transitioning from Child to Adult
- Swapping work assignments with another dweller who is on coffee break
- Returning from the wastelands
- Being replaced with someone of a higher skill in the current room the dweller occupies (When the room is at capacity).
With this in mind, if you wanted to force a dweller on a coffee break the easiest way to do so without changing any other assignments would be to send the dweller to the wastelands for a few seconds and then recall them.
YES. Send them out to wasteland and recall them right away. They will be on coffee break. Cheers!