After leaving the Show Stage he will go to the reception room, and then, he will randomly choose one of the two possible paths through the vents to your office, you can notice this by where his head is pointing to in the reception room.

1st Path: Orange will point to the right of your screen, indicating he will go to the Dining Area. Then he will use the hidden passage of the Show Stage to get to Parts and Service. After that, he will use the vent to get to the left of your office.

2nd Path: Orange will point to the left of your screen indicating he will go to the Prize Corner. Then, he will go through the vent of the Prize Corner to get in the bathrooms. And finally, he will use the vent in the bathrooms hallway to get to the right of your office.

After getting to your office, you will hear orange crawling in the vents, then you have to light up the vent where he is (if you dont he kills you), and then you have to press Z to punch him while hovering him with your mouse pointer (1st shift = 2 times. This will increase each shift), and after hitting him enough he will go away, if you miss a hit he will kill you.