Before you begin completing actions, which will save the lives of the next couple of guests, you must first reach the part of the residence, in which you have been before. Go from the starting point and into the main hall as fast as you can. You must reach there before the guests, that you have saved in the last mission.
Exactly in the metal cage, there is a hatch leading to the basement. Thanks to Grayson's mask you will be able to open it. It is enough that you approach it and hold the X button.
Now go into the basement and move through the linear chain of the next few chambers, until you reach the entrance to the upper level.
This way, you will find yourself in a secret chamber behind the bar of the residence. Use the available path, in order to exit the hiding place. Go directly to the room with the clock, which was the first starting point you have ever synchronized. Synchronise it again and restart the day.