The clue is on top of the elevator door.
Count all the bottles, lightbulbs, and door.
- Bottles = 9
- Lightbulbs = 9
- Door = 1
Based on the clue: bottle, bottle, bottle, lightbulb, lightbulb, door; The numbers will be 999991.
Tap the keypad on the left. Key in 999991.
Elevator opens. Welcome to level 39.