None of these things are what a janitor would normally do, but a credible story can come from any of them. To start a competitive company, Zulu might know that most of his fellow employees are disgruntled because of poor management and mistreatment. To hold the Sears Tower Hostage, he might accidentally damage the electrical room while cleaning and cause a power outage. Out of fear of being fired or arrested, he might lock himself in and refuse to open the doors. Only a few people at a time can leave the building because the elevators are out.
Word spreads through the entire building about what is happening and why.
His boss, a tyrant and an unfair taskmaster, is taken to task by everyone in the building and is asked to resign for creating an atmosphere in which such a thing can happen. The story is written up in the Chicago Tribune and he becomes a workingman's hero. After coming up with bizarre actions, eliminate the ones that won't work and keep the one that will.