For this, you only need to check the Freezer and the Lounge.

Watch the Freezer until Hourglass enters your office or the Freezer.

If he enters your office without entering the Freezer or the Lounge, he's using the Face's mechanic, so turn off the lights.

If he enters the Freezer and then your office without entering the Lounge, he's using the mechanic of Undying and Ace, so stand still.

If he enters the Freezer, then the Lounge, then your office, he took the path of P.N. Mickey, Oswald, or Impurity, so shut off a camera that isn't Lounge or Freezer.

Repeat until 6. A.M.

Brag about how you beat Night 6.

Done.