I was wondering what I would do. Mine is a variation on that... I think I would probably ask, “What shall I do with this? Would you like me to take it back?” Unless I’m passing the kitchen on the way out, I’m not sure I would make a special trip unescorted through someone’s offices.
The only times I’ve been offered coffee in someone else’s office it was in Styrofoam. I know how to deal with that...