"I'll have what's behind Door Number 3, please!" joke

I got this message detailing a first day of class experience from a
friend of a friend. His name is Kevin Stone, and he goes to Clemson
University.
Just a friendly reminder-look for door numbers...
So I'm looking for a class in Newman Hall- actually, I was looking
for Newman Hall- and, I thought i'd found it. no sign- no main
entrance.
So I walk around the building and find what I perceive to be an acutal
door with and actual doorknob. So I opened it.
Inside was a room at least 150x50- maybe half a football field- maybe
more- black concrete- 20ft ceiling.
Two guys in white overcoats.
A cow. Upside-down with hooves pointing into the air.
On some type of cart.
A chainsaw.
They were as embarrased to see me as I was to see them.
Everybody stared at everybody else for about 6 sec. (except the cow,
who was not facing me.) And I shut the door.
"Not econ."
I wasn't more than 10ft away from the door when I heard it lock.
I don't know what the hell they were doing, but they seemed to need
privacy.