Because someone has to cover the graveyard shift
Shift 1: The Morning People Shift 2: The Afternoon Crew Shift 4: The Night OwlsHere are the schedules for Shift 3:
Bob will be working from 12am-6am, Monday to Friday. He'll be eating Cheetos and playing video games
View Bob's ScheduleAlice will be working from 12am-6am, Tuesday to Thursday. She'll be drinking coffee and judging people on the internet
View Alice's Schedule