Ms. Casey, formerly known as Gemma, is the wife of Mark Scout. She is a former Russian literature professor at Ganz College and the former wellness counselor on the Severed Floor at Lumon Industries. She was considered a part-time employee, and it is generally accepted that those employees do not leave Lumon, though she believed that she had an outie. At the time of the events of season 1, Gemma was presumed to have died 2 years ago in a car crash, leaving Mark’s outie mourning and depressed. However, Mark’s innie discovered in The We We Are that she was still alive and was known as Ms. Casey.
At the end of her tenure as Wellness Director for the Severed floor, when she is sent down to the Testing Floor, Ms. Casey informs Mark that she had been alive for 107 hours, or just under the equivalent of 4.5 days, most of which was lived in short thirty-minute wellness sessions. Taking the full day she observed Helly R. into consideration, it could be presumed that she provided weekly wellness sessions for around a year, or served in that capacity less frequently for longer.