Julia Roberts never heard the last episode of the podcast.
Some of production designer Anastasia White's choices are subtle. For scenes at the facility that take place in 2018, she chose green exit signs; in later 2022-set episodes, the signs are red.
Before signing on to the series, Julia Roberts was a fan of the podcast, in which the role of Heidi was played by her friend Catherine Keener.
An aural cue from the Heidi and Walter's first sessions in the podcast, a bird call, carries over to the series, with a slight difference. Says co-creator Eli Horowitz, "It's a limpkin in the podcast, but apparently limpkins cannot be taken out of the wetlands for various legal reasons, so in the series, it's a pelican named Peggy."
The theme music from Brian De Palma's film "Body Double" was also used in this eposide (5).