That one has two places she can appear, she either hides as a red drawing of herself on a monitor or as a black and red blob in the gift shop on the floor. You click on her to send her back.
Other characters have sound ques to let you know they're in one of the hallways or the vent. Simply close the respective doors and wait for a sound que that they left. There's also the waitress that brings food, just click on her tray when she's in the hallway and she'll leave.
There's also the streamer who you need to check on and give her likes to satisfy her. And of course close all adds and ALWAYS answer the phone.
Lastly is the rat lady, when you see the greenish hands appear just wiggle your cursor over them to drive them away.