Hostile Workplace in Wisconsin?

I work at a small electronics repair shop as a technician. In my office I have one coworker who is my store manager. All tools and work space is provided by our company. I could sense some underlying tension today. Because of past intimidation from him regarding "his"desk and any unfinished projects on it, I asked our supervisor if I'm to finish the project. I was instructed to complete the task. I could tell this pissed him off but he waited several hours to confront me until after his supervisor left. IMMEDIATELY before bringing up the point to me, he was cleaning his pistol in his work bench. By the way, there are still more projects in queue at this time, but making a lot of noise and cleaning his gun seemed to be just the thing to set the mood for our talk. I was accused of defying his wishes by staying off his desk, to which i replied it was not his desk or tools and i was given permission, and I proceeded to call management. They advised me to punch out. I only left because i sincerely felt threatened and I'm terrified to return. Is this an example of hostile workplace in Wisconsin? Please let me know if i can provide any additional info