How can I follow Von Hess?

Hint 1 of 7:

The doorman must have a reason to believe someone is inside.

Hint 2 of 7:

Maybe if some noise came from that room, he would open the door to
investigate.

Hint 3 of 7:

Breaking glass would get the doorman's attention.

Hint 4 of 7:

Did you notice the blue partitions in the corner to the left of the door?

Hint 5 of 7:

The revolving dumbwaiter behind the partitions opens into the private room.

Hint 6 of 7:

The tray of glassware is too stable to tip over.  Make it off-balance.