I'm in the Office
This phrase is just a fancy way of saying you're stuck in the bathroom, probably trying to hide the fact that your pants are too tight and your butt is about to explode.
'I'm in the office', because your butt is about to fall off and you don't want your boss to see it.
'I'm in the office', you're trying to avoid getting caught with a half-eaten donut in your hand.
'I'm in the office', you're stuck in the bathroom, and your pants are making a loud noise.