Why did maniac paint 101 outside his door?

Maniac painted the number 101 outside his door to signify his new home and to claim a sense of belonging. It represented not only his physical space but also his desire for stability and acceptance in the community. By marking the door, he was establishing his identity and asserting that he was part of the family at the McNab household. This act symbolized his journey towards finding a place where he could feel safe and welcome.