At work too! I contract for a bunch of apartment complexes and I was trying to finish up a bathroom. I was putting a vinyl tub surround on the walls and I laid one off the pieces on top of an old table left behind. Utility knife in my right hand, of course just put a new blade in the knife. So my right hand was trimming just a little of the end, right hand was about a foot, foot and a half away from my body. Left hand was resting on top of the run surround I was cutting, also a foot to a foot and a half away from my body. Hands pretty far apart trying to be "safe". Well the knife slips off the vinyl and unbelievable I came across my whole body and chopped right where you see the cut. Not a slice, like an axe chopping wood. It felt like I hit it with a hammer. I knew the cut was gonna be bad because the new blade. Before I seen it I had a brand new microfiber towel (luckily) in my back pocket. I pulled it out and squeezed my thumb for a good minute until I got to look. No blood, at first lol. I seen the white and thought wtf, I cut to the bone!? Then the blood so I covered and squeezed again and took myself to the hospital which was about 7 minutes from where I was working. They say oh no, that's not the bone, that's your tendon that lifts your thumb up. I said I can move it though, well I could only bend it downward and it would go back straight. Doc says "try and give me a thumbs up" and nope, that thumb would not go up. The surgeon said I was only able to move that little bit because I cut 80% of it and 20% was still intact. He also said luckily it was a new blade because the cut was clean, no jagged or serrated edges that had to be trimmed back during surgery to stich the tendon back together. Im about 8 weeks after surgery and almost 7 weeks with physical therapy. Still very weak and shakes like crazy trying to move it. How well did you recover? That sounds painful as hell, the bicep distal tendon!?