That blows. I had the same thing happen to me when I was mounting one of my QS8s. I thought it was on the t-bracket and it wasn't. When I let it go, it stayed there for a few seconds before it dropped. Luckily for me, I broke it's fall by sacrificing the wall and my body. I ended up with two long gauges in the wall and a very large bruise on my leg and foot. Those things are heavy! The Q didn't incur any damage. Whew! After spackling and repainting the wall, things were good as new.