Stairs,four doors and a room ????

Saw this interesting structure today. Am totally baffled by what on earth this is...it's in a sheep paddock...is somebody secretly training sheep to be smart....to learn to escape....covert animal action in the Hinterland of Canterbury...I mean what is it??? Four stairs, leading to four doors...and a revolving door inside a small little room....is it a new sheep dip experience???
Come on ewe outdoor folk....what is this?? What do city dwellers have to fear here ?