Doesn't matter if it's a 9mm, some weird smaller shot made in a mormon weapons forge or a huge fuckin 50' cal. Any bullet of any size going through your neck is gonna kill ya, especially if it grazes or hits an artery like it did with Charlie. From what I was told by someone finishing up medical school; it looked like he immediately started stroking out or losing control of part of his brain if you checked his arms while he went down. It was likely the shot entered his neck and tumbled, reducing velocity or hit his spine and bounced into his brainstem. Disco Elysium has something on this if you ever got the check to dig around in the Hanged Man's throat.

I mean the odds of you surviving that is less than you straight up dying from it. What's crazy to me is that I would expect there to be a trauma team like right nearby. The public speaking event I attended had a whole medical suite with a trauma team, with security and this was before the Kirk incident. Then again..Utah. But yeah, with immediate trauma treatment it's likely he would have survived with some major brain damage or spinal damage depending on how the bullet tumbled. Blood gushing out of you like that so close to your brain with no exit wound or not means that your brain is going to have some severe damage as the blood quite literally pours out of it.