There are a couple of times when you'll want Xenia and Grigor to go take a hike for a while so you can rummage through their stuff. (You don't need Thanos or Niobe to leave; they have no stuff.)
Hint 2
Sometimes Xenia and Grigor just seem to wander off on their own. The first time you need them to go, however, you can trigger this by causing an accident backstage.
Hint 3
Try messing with the flies. That gets them both out of the way for a while, as does fixing the flies again.
