Irene says, “Thanks for not thinking I’m a serial killer. I guess.”
“Thanks for letting me throw up the worst New Year’s Eve of my life in your apartment,” Room 53 returns, and Irene cracks a tiny smile at that.

or,

Irene doesn't know her upstairs neighbor, really, but it's 5am and she won't stop ringing the doorbell; 3rd from the bottom prompt from this post.