Ivan has gone and gotten lost in this stupidly large house. The party's turnout hasn't spilled upstairs yet, so he can't ask for directions to the stairwell after having got turned around finding the lav, so he's opening doors. This is a closet. That is someone's office. That room has partially clothed people in it and they aren't pleased to see him. "Sorry." This room -

...the fuck?

It's not a stairwell, but when Ivan eventually finds the stairwell, if the hostess doesn't ask him not to steal her cool house contents that she meant to show off herself, he's going to present to somebody who needs impressing it as his own discovery. Which it is; he discovered it. In he goes to this oddly spacious empty bar.