I hate anything to do with suicide. I have a reflex where I empathize with situations and any time someone mentions suicide, especially with details as to the method, I have a hard time not picturing that moment over and over again from my own perspective.
We will never know what was going through his mind when he pulled the trigger, no matter how much we speculate. I can only tell you just reflexively empathizing that whatever it is must have been powerful. I wasn't a fan of Giambi in life, but it's hard not to feel for anyone in that much pain.
Depression sucks.