I think appendix carry is the fastest and most concealed way to carry a gun if you are physically capable of it.
That said, I cannot make myself carry a Glock pointed in the vicinity of my femoral artery.
I do not buy the Glock is as safe as a DA revolver. A DA revolver is at rest when you are carrying it. A Glock mainspring is "pre loaded" to some degree. It has to be. You can get a Glock down to a 3.5 LB trigger pull, that means alot of mainspring energy is already loaded up behind the striker. I know, if the striker were to slip off the trigger bar, the firing pin safety will catch the firing pin spring before the gun can fire. I got that. But, I also couldn't carry a cocked and locked 1911 pointed at my femoral artery either.
Realistically, I think the odds of the Glock going off by itself are very remote. I think your odds of winning the lottery, being struck by lightening etc (fill in your own "what are the chances?" phrase here) are much greater. But, thats a really bad place to get shot. And, I can't make myself do it.
DA revolver...DAK...TDA, yeah.
1911, Glock and, even to some degree HK's LEM, Not so much. (the jury is out on the HK LEM. The mainspring energy is stored, but, the hammer is down, I don't THINK it could fire if the sear let loose)