The Watcher had day shifts on some days, and night shifts on others. He didn’t have day and or night shifts on the same day as Johnny did. The Watcher worked day shifts on Monday, Wednesday, and Friday. He worked night shifts on Tuesday, Thursday, Saturday, and he got Sunday off. His job in jail had always been an assistant staff member with electrical work.
Circling back to his first thought in the morning, while The Watcher was doing his working shift, he had a little realization of why Johnny was starting to get suspicious. When he went to do his shift as an assistant electrical worker, he turned left to get to his work station. However, when Johnny did his shift as a cell cleaner, he turned right. Therefore, Johnny was never hanging out with The “all great” Watcher for most of the day.
Meanwhile, Johnny was closely examining and, seeing that The Watcher was starting to lose his outer veneer, and starting to show his true character.