I'd recommend using that nail nick as opposed to pinch gripping the blade, not really enough real estate there, for me at least, to get a good purchase on the blade and just a few minutes ago as I was going to use the knife to trim some leather, I ended up shaving a bit of epidermis off my index finger pad, no blood

but enough to tell me 'hey that's not cool' And the knife worked exceptionally well trimming the leather that I needed to attend to, so, that's good
My method of opening a stiff folder as safely as I can is as follows;
Thumbnail firmly into the nail nick, as far from the pivot end so as to gain as much mechanical advantage as I can.
Then, with my other hand, I will pull the handle away from the blade, while keeping my thumbnail into the nail nick stationary. Until it is at least halfway open then I will pinch grab the blade and open the rest of the way.
This way of opening you have more control, instead of trying to pull a strong blade out of the handle by your thumbnail, you keep the thumbnail stationary so it is just anchoring the blade in one spot, while you are able to grip the much larger part, the handle, and PULL the handle away from the blade. For me it works pretty good.
G2