One of my coworkers I have worked with for many years we working on a new Heating as well as Air Conditioning installation appointment! We were installing a new Heating as well as Air Conditioning system in a new construction building, but they were still completing some of the construction process. There was pieces of debris everywhere, but i was now working on the study room ductwork installation, while my coworker was in another room of the condo. Due to the fact that the construction project was not completed, the two of us could hear & see each other while the two of us were doing the majority of the work. My coworker was busy installing ductwork above the master study room area. I heard a violent scream from that section of the house. I jumped down from the ladder, & ran into that section of the building. My coworker sliced off one of his fingers, when he dropped a piece of sheet metal. On most jobs we have special gloves for handling sheet metal, even though he wasn’t wearing them. I did not feel what to do, & I I was trying not to have a panic attack. There was red blood everywhere. I picked up the finger, even though it was covered in drywall dust & sawdust. I called my boss & got my coworker into the car. I then took my coworker to the nearest hospital, which was only 5 minutes away. I presented them with the middle finger & told them the story. I waited for my boss to arrive, & they both disappeared behind the emergency room doors, but a few minutes later, my boss expected myself and others to return to the Heating and Air Conditioning installation sight. I was still in shock, & I felt ill, sweaty, & nauseous. I wasn’t going to return to that building ever in a thousand years.